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The majority of Golgi glycosyltransferases are type II membrane proteins with a small cytosolic tail at their N-terminus. Several mechanisms for localizing these glycosyltransferases to the Golgi have been proposed. In Saccharomyces cerevisiae, the phosphatidylinositol-4-phosphate-binding protein ScVps74p interacts with the cytosolic tail of a Golgi glycosyltransferase and contributes to its localization. In this study, we investigated whether a similar mechanism functions in the fission yeast Schizosaccharomyces pombe. First, we identified gpp74+ (GPP34 domain-containing Vps74 homolog protein), a gene encoding the S. pombe homolog of S. cerevisiae Vps74p. Deletion of the gpp74+ gene resulted in the missorting of three Golgi glycosyltransferases, SpOch1p, SpMnn9p, and SpOmh1p, to vacuoles, but not SpAnp1p, indicating Gpp74p is required for targeting some glycosyltransferases to the Golgi apparatus. Gpp74p with an N-terminal GFP-tag localized to both the Golgi apparatus and the cytosol. Golgi localization of Gpp74p was dependent on the phosphatidylinositol 4-kinase SpPik1p. Site-directed mutagenesis of hydrophobic and basic amino acids in the cytosolic tails of SpOch1p and SpMnn9p resulted in their missorting to vacuoles, indicating these cytosolic N-terminal residues are important for localization in the Golgi. Unexpectedly, no prominent alternations in protein glycosylation were observed in S. pombe gpp74Δ cells, probably due to the residual Golgi localization of some SpOch1p and SpMnn9p in these cells. Collectively, these results demonstrate that both Gpp74p-dependent and Gpp74p-independent mechanisms are responsible for the Golgi localization of glycosyltransferases to the Golgi in S. pombe. KEY POINTS: • Gpp74p is involved in the localization of glycosyltransferases to the Golgi. • The cytosolic tails of glycosyltransferases are important for Golgi localization. • Gpp74p localizes to the Golgi in a SpPik1p-dependent manner.

Soluble proteins destined for the secretory pathway contain an N-terminal signal peptide that induces their translocation into the endoplasmic reticulum (ER). The importance of N-terminal signal peptides for ER translocation has been extensively examined over the past few decades. However, in the budding yeast Saccharomyces cerevisiae, a few proteins devoid of a signal peptide are still translocated into the ER and then N-glycosyl-ated. Using signal peptide-truncated reporter proteins, here we report the detection of significant translocation of N-terminal signal peptide-truncated proteins in a yeast mutant strain (ste24Δ) that lacks the endopeptidase Ste24 at the ER membrane. Furthermore, several ER/cytosolic proteins, including Sec61, Sec66, and Sec72, were identified as being involved in the translocation process. On the basis of screening for 20 soluble proteins that may be N-glycosylated in the ER in the ste24Δ strain, we identified the transcription factor Rme1 as a protein that is partially N-glycosylated despite the lack of a signal peptide. These results clearly indicate that some proteins lacking a signal peptide can be translocated into the ER and that Ste24 typically suppresses this process.

Endoplasmic reticulum (ER)-associated degradation (ERAD) is a proteolytic pathway for handling misfolded or improperly assembled proteins that are synthesized in the ER. Cytoplasmic peptide:N-glycanase (PNGase) is a deglycosylating enzyme that cleaves N-glycans that are attached to ERAD substrates. While the critical roles of N-glycans in monitoring the folding status of carrier proteins in the ER lumen are relatively well understood, the physiological role of PNGase-mediated deglycosylation in the cytosol remained poorly understood. We report herein the identification of endogenous substrates for the cytoplasmic PNGase in Saccharomyces cerevisiae. Using an isotope-coded glycosylation site-specific tagging (IGOT) method-based LC/MS analysis, 11 glycoproteins were specifically detected in the cytosol of PNGase-deletion cells (png1Δ). Among these molecules, at least five glycoproteins were clearly identified as ERAD substrates in vivo. Moreover, four out of the five proteins were found to be either deglycosylated by PNGase in vivo or the overall degradation was delayed in a png1Δ mutant. Our results clearly indicate that the IGOT method promises to be a powerful tool for the identification of endogenous substrates for the cytoplasmic PNGase.

In the presence of catalytic amounts of platinum(II) chloride and silver(I) hexafluoroantimonate, (Z)-alkenylsilanes reacted with various carbon electrophiles (acetals, aminals, carboxylic anhydrides, alkyl chlorides, etc.) at the γ-position to give allylation products. A plausible mechanism for the platinum-catalyzed allylation involves alkene migration of alkenylsilanes to allylsilanes and subsequent allylation of carbon electrophiles, both of which are catalyzed by a cationic platinum(II) species.

In the presence of catalytic amounts of PtCl2 and AgSbF6, (Z)-alkenylsilanes react with various carbon electrophiles at the γ-position to give allylation products. A plausible mechanism for the Pt-catalyzed allylation involves alkene migration of alkenylsilanes to allylsilanes and subsequent allylation of carbon electrophiles.

C-Mannosylation, a protein-modification found in various eukaryotes, involves the attachment of a single mannose molecule to selected tryptophan residues of proteins. Since C-mannosyl tryptophan (CMW) was detected in human urine, it is generally thought that CMW is not catabolized inside our body and instead is excreted via the urine. This paper reports enrichment of a bacterial consortium from soil that degrades CMW. The bacteria grew in minimal medium supplemented with CMW as the carbon source. Interestingly, even after successive clonal picks of individual colonies, several species were still present in each colony as revealed by 16S rRNA gene sequence analysis, indicating that a single species may not be responsible for this activity. A next generation sequencing (NGS) analysis was therefore carried out in order to determine which bacteria were responsible for the catabolism of CMW. It was found that a species of Sphingomonadaceae family, but not others, increased with simultaneous decrease of CMW in the media, suggesting that this species is most likely the one that is actively involved in the degradation of CMW.

Three procedures for the allylation of acetals and aminals with (Z)-1-trimethylsilylalkenes are elaborated: direct allylation, three-component reaction of the respective aldehyde, orthoformate or carbamate, and silylalkene, and pretreatment of the silylalkene followed by addition of acetal or aminal.

The functions of two Schizosaccharomyces pombe Vps9-like genes, SPBC4F6.10/vps901(+) and SPBC29A10.11c/vps902(+), were characterized. Genomic sequence analysis predicted that Vps901p contains a VPS9 domain, whereas cDNA analyses revealed that Vps901p contains a CUE domain (coupling of ubiquitin to ER degradation) in its C-terminal region. Deletion of vps901(+) resulted in mis-sorting and secretion of S. pombe vacuolar carboxypeptidase Cpy1p, whereas deletion of vps902(+) had no effect, suggesting that only Vps901p functions in vacuolar protein transport in S. pombe. Deletion of vps901(+) further produced pleiotropic phenotypes, including vacuolar homotypic fusion and endocytosis defects. Heterologous expression of the budding yeast VPS9 gene corrected the CPY mis-sorting defect in vps901Δ cells. These findings suggest that the VPS9 domain of Vps901p is required for vacuolar protein trafficking in S. pombe.

In eukaryotic cells, SNARE proteins are essential for intracellular vesicle trafficking. Several SNARE proteins are required for vacuolar protein transport and vacuolar biogenesis in Saccharomyces cerevisiae. Previously we demonstrated that one of the fission yeast SNARE proteins, Pep12p, is not required for vacuolar fusion process in Schizosaccharomyces pombe. We have re-examined the function of S. pombe Pep12p using the newly created pep12(+) deletion strain. Deletion of the fission yeast pep12(+) gene results in pleiotropic phenotypes consistent with the absence of normal vacuoles, including missorting of vacuolar carboxypeptidase Y-and various ion- and drug-sensitivities. GFP-Pep12 fusion protein is mostly localized at the vacuolar membrane and the prevacuolar compartment. The S. pombe pep12Δ mutation phenocopies that of vps33Δ, suggesting that both Pep12p and Vps33p act at the same membrane fusion step in S. pombe, and both mutations cause vacuolar deficiency.

Endoplasmic reticulum (ER)-associated degradation (ERAD) is a quality control system for newly synthesized proteins in the ER; nonfunctional proteins, which fail to form their correct folding state, are then degraded. The cytoplasmic peptide:N-glycanase is a deglycosylating enzyme that is involved in the ERAD and releases N-glycans from misfolded glycoproteins/glycopeptides. We have previously identified a mutant plant toxin protein, RTA (ricin A-chain nontoxic mutant), as the first in vivo Png1 (the cytoplasmic peptide:N-glycanase in Saccharomyces cerevisiae)-dependent ERAD substrate. Here, we report a new genetic device to assay the Png1-dependent ERAD pathway using the new model protein designated RTL (RTA-transmembrane-Leu2). Our extensive studies using different yeast mutants identified various factors involved in RTL degradation. The degradation of RTA/RTL was independent of functional Sec61 but was dependent on Der1. Interestingly, ER-mannosidase Mns1 was not involved in RTA degradation, but it was dependent on Htm1 (ERAD-related α-mannosidase in yeast) and Yos9 (a putative degradation lectin), indicating that mannose trimming by Mns1 is not essential for efficient ERAD of RTA/RTL. The newly established RTL assay will allow us to gain further insight into the mechanisms involved in the Png1-dependent ERAD-L pathway.

In Saccharomyces cerevisiae, three classes of sphingolipids contain myo-inositol – inositol phosphorylceramide (IPC), mannosylinositol phosphorylceramide (MIPC) and mannosyldiinositol phosphorylceramide [M(IP)2C]. No fission yeast equivalent of Ipt1p, the inositolphosphotransferase that synthesizes M(IP)2C from MIPC, has been found in the Schizosaccharomyces pombe genome. Analysis of the sphingolipid composition of wild-type cells confirmed that MIPC is the terminal and most abundant complex sphingolipid in S. pombe. Three proteins (Sur1p, Csg2p and Csh1p) have been shown to be involved in the synthesis of MIPC from IPC in S. cerevisiae. The S. pombe genome has three genes (SPAC2F3.01, SPCC4F11.04c and SPAC17G8.11c) that are homologues of SUR1, termed imt1+, imt2+ and imt3+, respectively. To determine whether these genes function in MIPC synthesis in S. pombe, single and multiple gene disruptants were constructed. Single imt disruptants were found to be viable. MIPC was not detected and IPC levels were increased in the triple disruptant, indicating that the three SUR1 homologues are involved in the synthesis of MIPC. GFP-tagged Imt1p, Imt2p and Imt3p localized to Golgi apparatus membranes. The MIPC-deficient mutant exhibited pleiotropic phenotypes, including defects in cellular and vacuolar morphology, and in localization of ergosterols. MIPC seemed to be required for endocytosis of a plasma-membrane-localized amino acid transporter, because sorting of the transporter from the plasma membrane to the vacuole was severely impaired in the MIPC-deficient mutant grown under nitrogen-limiting conditions. These results suggest that MIPC has multiple functions not only in the maintenance of cell and vacuole morphology but also in vesicular trafficking in fission yeast.

The budding yeast Saccharomyces cerevisiae is able to utilize glycerol as the sole carbon source via two pathways (glycerol 3-phosphate pathway and dihydroxyacetone [DHA] pathway). In contrast, the fission yeast Schizosaccharomyces pombe does not grow on media containing glycerol as the sole carbon source. However, in the presence of other carbon sources such as galactose and ethanol, S. pombe could assimilate glycerol and glycerol was preferentially utilized over ethanol and galactose. No equivalent of S. cerevisiae Gcy1/glycerol dehydrogenase has been identified in S. pombe. However, we identified a gene in S. pombe, SPAC13F5.03c (gld1 +), that is homologous to bacterial glycerol dehydrogenase. Deletion of gld1 caused a reduction in glycerol dehydrogenase activity and prevented glycerol assimilation. The gld1Δ cells grew on 50 mM DHA as the sole carbon source, indicating that the glycerol dehydrogenase encoded by gld1 + is essential for glycerol assimilation in S. pombe. Strains of S. pombe deleted for dak1 + and dak2 + encoding DHA kinases could not grow on glycerol and showed sensitivity to a higher concentration of DHA. The dak1Δ strain showed a more severe reduction of growth on glycerol and DHA than the dak2Δ strain because the expression of dak1 + mRNA was higher than that of dak2 +. In wild-type S. pombe, expression of the gld1 +, dak1 +, and dak2 + genes was repressed at a high concentration of glucose and was derepressed during glucose starvation. We found that gld1 + was regulated by glucose repression and that it was derepressed in scr1Δ and tup12Δ strains.

In the presence of catalytic amounts of PtCl(2) and metal iodides, beta-substituted vinylsilanes reacted with aldehydes at the beta-position to give allyl silyl ethers. The Pt-catalyzed addition to aromatic aldehydes proceeded efficiently in the presence of LiI. The combined use of PtCl(2) and MnI(2) was found to be effective in addition to aliphatic aldehydes.

Sterols are a major class of membrane lipids in eukaryotes. In Schizosaccharomyces pombe, sterol 24-C-methyltransferase (Erg6p), C-8 sterol isomerase (Erg2p), C-5 sterol desaturase (Erg31p, Erg32p), C-22 sterol desaturase (Erg5p) and C-24 (28) sterol reductase (Sts1p/Erg4p) have been predicted, but not yet determined, to catalyse a sequence of reactions from zymosterol to ergosterol. Disruption mutants of these genes were unable to synthesize ergosterol, and most were tolerant to the polyene drugs amphotericin B and nystatin. Disruption of erg31(+) or erg32(+) did not cause ergosterol deficiency or tolerance to polyene drugs, indicating that the two C-5 sterol desaturases have overlapping functions. GFP-tagged DRM (detergent-resistant membrane)-associated protein Pma1p localized to the plasma membrane in ergDelta mutants. DRM fractionation revealed that the association between Pma1-GFP and DRM was weakened in erg6Delta but not in other erg mutants. Several GFP-tagged plasma membrane proteins were tested, and an amino acid permease homologue, SPBC359.03c, was found to mislocalize to intracellular punctate structures in the ergDelta mutants. These results indicate that these proteins are responsible for ergosterol biosynthesis in fission yeast, similar to the situation in Saccharomyces cerevisiae. Furthermore, in fission yeast, ergosterol is important for plasma membrane structure and function and for localization of plasma membrane proteins.

Z-Alkenylsilanes are used as γ-substituted allylsilane precursors for the allylation of carbon electrophiles such as aryl and alkyl acetals and aminals which may be synthesized in situ from the corresponding aldehyde and ortho-formate or methyl carbamate, respectively.

Significance In the endoplasmic reticulum (ER), N-glycans on glycoproteins play important roles in dictating the folding status of proteins by a sophisticated N-glycan–dependent protein quality control machinery. In this study we identified the dysregulation of ER-associated degradation (ERAD) in cells that were defective in the cytosolic deglycosylating enzyme, Ngly1. ERAD dysregulation was caused by an unexpected deglycosylating activity of endo-β- N -acetylglucosaminidase, another cytosolic deglycosylation enzyme, and this action resulted in the intracellular formation of protein aggregates. Our results clearly point to the critical role of N-glycans even in cytosolic events of the ERAD process by controlling the conformation/solubility of proteins. This study may also provide a potential mechanism for explaining the pathology of a human genetic disorder caused by mutations in the NGLY1 gene.

In the presence of a stoichiometric or catalytic amount of a Lewis acidic indium(III) salt, allylsilanes reacted intramolecularly with unactivated terminal alkynes to give cyclized products in good to high yields. The fact that the reaction proceeded in a trans-addition mode suggests a reaction mechanism via electrophilic activation of the triple bond by the indium salt.

Glycosylphosphatidylinositol (GPI)-anchored proteins are essential for normal cellular morphogenesis and have an additional role in mediating cross-linking of glycoproteins to cell wall glucan in yeast cells. Although many GPI-anchored proteins have been characterized in Saccharomyces cerevisiae, none have been reported for well-characterized GPI-anchored proteins in Schizosaccharomyces pombe to date. Among the putative GPI-anchored proteins in S. pombe, four alpha-amylase homologs (Aah1p-Aah4p) have putative signal sequences and C-terminal GPI anchor addition signals. Disruption of aah3(+) resulted in a morphological defect and hypersensitivity to cell wall-degrading enzymes. Biochemical analysis showed that Aah3p is an N-glycosylated, GPI-anchored membrane protein localized in the membrane and cell wall fractions. Conjugation and sporulation were not affected by the aah3(+) deletion, but the ascal wall of aah3Delta cells was easily lysed by hydrolases. Expression of aah3 alleles in which the conserved aspartic acid and glutamic acid residues required for hydrolase activity were replaced with alanine residues failed to rescue the morphological and ascal wall defects of aah3Delta cells. Taken together, these results indicate that Aah3p is a GPI-anchored protein and is required for cell and ascal wall integrity in S. pombe.

In the presence of a catalytic amount of LiCl, α-dimethylsilylesters (a-DMS-esters) 1 smoothly reacted with various aldehydes at 30 °C to give aldols in good to high yields. On the other hand, the aldol reaction with ketones was effectively promoted by MgCl 2 rather than by LiCl. α-Enones also underwent the metal chloride-promoted addition of 1 at the carbonyl carbon or β-carbon.

In the presence of LiCI, dibutylchlorostannane (Bu 2 SnClH) reacted with γ-unsubstituted propargyl alcohols and ethers to give γ-stannylated allyl alcohols and ethers, respectively, with high regio- and stereoselectivity. These vinylstannane products could be successfully utilized for the Pd-catalyzed cross-coupling reaction.

A catalytic amount of In(OAc) 3 smoothly promoted 1,4-reduction of certain α-enones with PhSiH 3 in ethanol at ambient temperature. The intermediary enolates could be used for inter- and intramolecular aldol reactions andintramolecular Michael addition.

Our research works in the last few decades are summarized. We have studied the synthetic use of organometallics, especially organosilicon compounds, and have developed a number of new reagents and ...

In the presence of an acid catalyst, alpha-alkyl-substituted (Z)-vinylsilanes 1, bearing a tosylamino group, were smoothly cyclized to trans-2-alkyl-3-silylpiperidines 2 (1,2-silyl-migration products) and (2R*, 1'S*)-2-(1'-silylalkyl)pyrrolidines 3. The elaboration of the reaction conditions enabled the selective preparation of each cyclized product. The acid-catalyzed cyclization of (Z)-vinylsilane 5, whose methylene tether is shorter than that of 1 by one carbon, formed only the 1,2-silyl-migration product 6 with high trans-selectivity. These cyclizations were found to proceed in a stereospecific manner.

In this paper, we propose using a disaggregative behavioral model in choice of bicycle-parking place, and using the Alternative Hieratical Process (AHP) as the method for grasping consciousnesses of illegality.First, we did a cluster analysis using the score of AHP, and carried out segmentation of the sample. As a result, we made two segments with completely different consciousness about illegal parking. Moreover, we observed that the utility functions of these two segments, considered from the disaggregative behavioral model built for every segment, differ clearly.Finally, We verified the validity of using the model built by sensitivity analysis.

Peptide:N-glycanase (PNGase) is a deglycosylating enzyme that acts on N-glycoproteins. A growing evidence exists to indicate that the cytosolic form of PNGase, which is ubiquitously distributed throughout eukaryotes, is not only implicated in the efficient degradation of misfolded glycoproteins destined for the proteasomal degradation but also in the generation of free oligosaccharides as the initial step in the non-lysosomal catabolism of N-glycans. This article summarizes the current state of our knowledge of the physiological and molecular functions of the cytosolic PNGase in a model organism, Saccharomyces cerevisiae, and also discusses the functional/structural diversities of this molecule within eukaryotes.

Background Endoplasmic reticulum (ER)-associated degradation (ERAD) is a pathway by which misfolded or improperly assembled proteins in the ER are directed to degradation. The cytoplasmic peptide: N -glycanase (PNGase) is a deglycosylating enzyme that cleaves N -glycans from misfolded glycoproteins during the ERAD process. The mutant form of yeast carboxypeptidase Y (CPY*) is an ERAD model substrate that has been extensively studied in yeast. While a delay in the degradation of CPY* in yeast cells lacking the cytoplasmic PNGase (Png1 in yeast) was evident, the in vivo action of PNGase on CPY* has not been detected. Methods We constructed new ERAD substrates derived from CPY*, bearing epitope tags at both N- and C-termini and examined the degradation intermediates observed in yeast cells with compromised proteasome activity. Results The occurrence of the PNGase-mediated deglycosylation of intact CPY* and its degradation intermediates was evident. A major endoproteolytic reaction on CPY* appears to occur between amino acid 400 and 404. Conclusions The findings reported herein clearly indicate that PNGase indeed releases N -glycans from CPY* during the ERAD process in vivo . General Significance This report implies that the PNGase-mediated deglycosylation during the ERAD process may occur more abundantly than currently envisaged.

The radical-initiated β-ketoalkylation of haloalkanes with tributylstannyl enolates is described. Stannyl enolates derived from aromatic ketones are reactive toward the homolytic β-ketoalkylation of simple haloalkanes as well as those activated by an electron-withdrawing group. The reactivity of stannyl enolates as radical alkylating agents can be utilized for an efficient three-component coupling reaction among stannyl enolates, haloalkanes, and electron-deficient alkenes.

In the presence of a radical initiator, allyltributylstannanes bearing an electron-withdrawing group at the β-position smoothly reacted with electron-deficient terminal alkenes to give allylstannylated products in good yields. The stannyl group was introduced into the terminal carbon with high regioselectivity. The allylstannylation of homochiral 8-phenylmenthyl acrylate proceeded with moderate to good diastereoselectivity. Terminal and electron-deficient internal alkynes as well efficiently underwent the radical-initiated allylstannylation in an anti addition mode. The reaction of terminal alkynes showed the same regioselectivity as that of terminal alkenes. The present radical reaction was applicable to allylation of aromatic aldehydes and ketones.

The Michael addition of β-keto esters to 3-buten-2-one (methyl vinyl ketone, MVK) in the presence of a pentacoordinate organosilicate was investigated. Ethyl 2-oxo-1-cyclohexanecarboxylate reacted with MVK in the presence of potassium bis(1,2-benzenediolato)phenylsilicate to furnish ethyl 2-oxo-1-(3-oxo-1-butyl)-1-cyclohexanecarboxylate in 96% isolated yield. Ethyl 2-oxo-1-cyclopentanecarboxylate, ethyl 2-oxo-1-cyclooctanecarboxylate, ethyl 2-methyl-3-oxobutanoate, and ethyl 2-ethyl-3-oxobutanoate also reacted with MVK in the presence of potassium bis(1,2-benzenediolato)phenylsilicate to produce the corresponding 1,4-adduct in moderate to good yields. In these reactions, the silicate might work as both a Lewis acid catalyst and a Bronsted base catalyst at the same time.

This study analyzes the structure of Jeepneys' high road occupancy at terminal areas in Metro Manila. By the interview survey for drivers and leaders of driver and operator associations, the present situation regarding operational cost and structure, and relationship between the characteristics of terminal and operational behaviors are comprehended. Based on these, the Jeepney transport market model was built and the behaviors of Jeepney at terminal area were expressed.Results show that drivers tend to wait until their Jeepneys are fully occupied and there is possibility that the number of operating vehicles will increase by increasing the terminal fee.

In the presence of a catalytic amount of TsOH or TiCl4, (Z)-5-silyl-4-penten-1-ols ((Z)-1) are smoothly cyclized to 2-silylmethyl-substituted tetrahydrofurans. This cyclization is applicable to the construction of a tetrahydropyran ring. The silyl group and the geometry of the C−C double bond strongly influence the cyclization rate. TBDMS and benzyldimethylsilyl groups considerably accelerate the cyclization in comparison with a dimethylphenylsilyl group, and (E)-vinylsilanes show much lower reactivity than the corresponding (Z)-isomers. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes 17, 19, and 21, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity. The silyl group of some cyclized products can be easily converted into a hydroxy group with stereochemical retention.

The Cu(I)-catalyzed boration of an α,β-enone using a diboron is described. Combination of a Cu(I) salt and tributylphosphine is an effective catalyst system, though the individual use of Cu(I) and tributylphosphine is not active for the reaction.

A benzyldimethylsilyl (BnDMS) group was found to effectively enhance the reactivity of vinylsilanes toward the acid-catalyzed intramolecular addition of a hydroxy group in comparison with a dimethylphenylsilyl group. The BnDMS group of the resultant cyclized products could be easily converted to a hydroxy group by the action of TBAF–H2O2–KHCO3.

In the presence of an acid catalyst, vinylsilanes 1 bearing an amino group protected by an electron-withdrawing group were smoothly cyclized to 2-(silylmethyl)pyrrolidines 2. This cyclization was utilized for the stereoselective synthesis of 2,n-disubstituted pyrrolidines (n = 3−5). The cyclized products could be converted to the corresponding alcohols by oxidative cleavage of the carbon−silicon bond with TBAF and H2O2.

In the presence of AIBN or Et3B, a variety of vinyl iodides reacted with allylstannanes bearing an electron-withdrawing group at the β-position to afford 1,4-dienes in moderate to good yields. The allylation showed high stereoselectivity when the α-substituent of the iodides was a phenyl group, or the β-substituent was a bulky group.

This paper describes an unprecedented catalytic reaction using Au(I) complexes. Au complexes efficiently catalyze dehydrogenative dimerization of trialkylstannanes. Catalytic activity of the Au(I) complex toward dehydrogenative dimerization of the trialkylstannane is extremely high (0.1 mol%, 48 h) comparable to that of Pd catalysts. The synthetic generality of this reaction was demonstrated for the reaction using tributyl-, trioctyl-, triphenylstannane.

Highly stereoselective metathesis reactions between optically active silyl compounds and copper(I) salts in 1,3-dimethyl-2-imidazolidinone (DMI) are reported. The substitution reaction of (+)-α-naphthylphenylmethylsilane with a mixture of lithium tert-butoxide and copper(I) salt smoothly proceeded in DMI to give the corresponding silyl ether with a high degree of retention of the configuration in a quantitative yield. The use of DMI as a solvent and the presence of a chloride ion are necessary for this reaction. An optically active alkynylsilane also reacted with the mixed reagent to afford the corresponding silyl ether. A mechanism of oxidative addition of the hydrosilane and reductive elimination of the silyl ether on copper is proposed.

Hydroxy esters are reduced by trimethoxysilane in the presence of a catalytic amount of lithium methoxide to yield diols, while for simple esters the alcohol exchange reaction takes place preferentially. Through the exchange reaction, lactones without a hydroxy group are reduced. Tosylimines are also reduced in the system.

This study analyzes the parking behavior at route ends of fixed-route paratransit in Metro Manila called “jeepney”, focusing on variation with passenger volume during peak and off-peak hours. In most cases (90.3%), jeepneys park on-street at the route-ends while waiting for passengers. This parking behavior can cause street congestion. Waiting time varies with passenger demand such that parking duration is longer during peak hours. The study will propose a simulation model which can explain the hourly variation of parking duration and volume of parked jeepneys. The appropriateness of the model will be tested using data gathered from a survey.