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This article describes the basic radical reactivity of organoboranes toward generating carbon-centered radicals via cleavage of carbon-boron bonds. Research interests in the utilization of organoboranes as radical initiators and radical precursors are also discussed.

Research describes the preparation of a series of novel phosphine-phosphite ligands containing a chiral phosphine moiety, which serve as ligands in the palladium catalyzed allylic alkylation reactions. The reaction of diphenyl-2-propenyl acetate with dimethyl malonate, mediated by these ligands exhibits good enantioselectivities.

Research explores the synthesis of cyclodextrin derivatives containing the same substituent for the hydroxyl groups at the 2-, 3-, and 6-position. Data discuss the electrophilic reaction mediating the production of the monoalkylated cyclodextrin derivatives.

Results show that by nucleophilic substitution of the allylic bromine in 2-bromomethyl-7-4'-dimethoxyisoflavone using either ethyl cyanoacetate, or cyanide anions, or palladium-catalyzed ethoxycarbonylation, bridged bis-isoflavones can be prepared. Data indicate that a double alkylation reaction leads to the formation of bis-isoflavones.

A synthetic route to P-chirogenic trialkylphosphine-boranes involves an optically active secondary dialkylphosphine-borane as an intemediate. Research shows that the methodology is applicable for the synthesis of analogous phosphine-boranes and phosphine ligands.

Research discusses the use of the palladium-catalyzed asymmetric allylic alkylation (AAA) reaction in the synthesis of barbituric acid derivatives, cyclopentobarbital and pentobarbital, at 91% and 81% yield, respectively.

1-(Alkylamino)-3,5-dichloro-2,4,6-trinitrobenzenes were synthesized through aromatic substitution reactions that involve sym trichlorotrinitrobenzene and amines. The yields and relative formation were found to be a function of the degree of alkylation of the nucleophile. For ammonia and monoalkylamines, the introduction of a second and third donor was supported. The findings were attributed to the intramolecular hydrogen bonding as verified by X-ray analysis of 3,5-dichloro-2,4,6-trinitroaniline.

Bivalent sialyl Lewis x derivatives and sialyl Lewis x carboxylic acids were chemoenzymatically synthesized to investigate their inhibitory activities. The products underwent assaying to test for inhibition against binding of a sLe(super a)-polymer to immobilized E- and P-selectin. For the E-selectin assay, all dimers had smaller IC50 values compared to the sLe(super x) monomer. The results further showed that comparable binding improvements can be achieved with linkers of totally different rigidity and length.

The alkylation and reductive decyanation of cyanohydrin acetonides or 4-cyano-2,2-dimethyl-1,3-dioxanes involved deprotonation reactions that led to the formation of an intermediate product. The nitrile group of the intermediate cyanohydrins product was then replaced by an axial hydrogen after reductive decyanation which led to the formation of acetonide-protected syn-1,3-diols. Furthermore, cyanohydrin acetonides are the key intermediates of roflamycoin and roxaticin.

The (-)-tetrahydropalmatine having a C(9) and C(10) D-ring pattern is synthesized from ortho-substituted hydroxymethyl- benzene, an ortho-substituted electrophile having a 94:6 mixture of enantiomer. The electrophile has the capacity to break the lithium formamidine chelate and reduce the selectivity during alkylation. The positioning of carbethoxy substituent in the ortho region of the suitable benzyl derivative generate the D-ring substitution pattern. The experimental procedure for the synthesis of (plus or minus)-canadine is discussed.

Palladium-pi-allyl alkylations under mild and high regioselective conditions result in the formation of a 10-membered lactam which can be used to synthesize CGS25155. The methodology eliminates chiral auxillary based resolution and allows the inclusion of methylene at the C-9 position. The stereoselectivity of thioacetate 1,4-addition can be increased by using this method. The experimental procedure for the synthesis of CGS25155 is discussed.

Reaction between 2-pyrrolidinone (2) and an iodoalkane (1) results in the formation of 2-(perfoluoralkyl)ethanols(R(sub F)CH2CH2OH). C6F13CH2CH2OH (3) is formed in 83% yield due to alkylation of 2 by heating with 1. The perfluoroalkylated long chain alcohols display strong surface activity in solution. A lactim salt is formed due to nucleophilic displacement on the iodoalkane by O-attack of the ambidentate lactam. Thermal alkylation of lactam ether occurs through S(sub N)2 displacement of alcohol by N-attack of lactam followed by fragmentation of the lactim to lactim and the alkene.

Synthesis of butenolides and pentenolides involves ruthenium-catalyzed addition of corresponding alkenes to 4-hydroxy-2-alkynoates in an Alder-ene-type fashion. Excellent chemoselectivity is observed in the reaction, and polarization of the alkynes does not influence the reaction. Examination of the regioselectivity of the reaction reveals that the reaction proceeds through contra-electronic alpha-alkylation of hydroxyalkynoates. Stereochemical integrity of the propargylic position is maintained during the reaction. A simple acetogenin (+)-ancepsenolide is prepared using this reaction.

Synthesis of trihydroxylated pyrrolidines from tartrimide involves stereoselective intermolecular cis-amidoalkylations on an acyliminium intermediate. Tin reagents facilitate cis-amidoalkylations, and OTBS group in the presence of MgBr2 regulates the stereoselectivity. New methods involving selective protection, reduction of the amide group and functionalization of the unsaturated bonds help prepare various pyrrolidine derivatives as potential glycosidase inhibitors.

The reagent methyl acrylate is prepared by esterification of the 3,3'-dithiodipropionic acid. Data indicate that the in situ generation of the methyl acrylate demonstrates the introduction of a propionate moeity onto nitrogen heterocycles.

The benzyltrimethylammonium (BTMA) enolates of 2-methylcyclohexanone were utilized to determine the effects of nonmetal cations on the alkylation of alpha-substituted aldehydes. The synthetic process involves the reaction of an aldehyde and iodomethane with the alkylating agent which led to the formation of 2,4-dinitrophenylhydrazone. Furthermore, the alkylating agent was utilized for the formation of several alpha-substituted aldehydes.

An effective method for the synthesis of configurationally pure (E,E)-, and (Z,E)-dienes bearing alpha- and alpha,beta-stereogenic centers using the transition metal-catalyzed reactions was designed. Pd(0)-catalyzed cross-coupling reaction of (E)-trisubstituted vinyl-zinc intermediates interact with (E)- and (Z)-vinyl iodides. Reactions involving (Z)-isomers were favored when PdCl2(PPh3)2-DIBAL was used.

The benzyltrimethylammonium (BTMA) enolates of 2-methylcyclohexanone were utilized to determine the effects of nonmetal cations on the alkylation of alpha-substituted aldehydes. The synthetic process involves the reaction of an aldehyde and iodomethane with the alkylating agent which led to the formation of 2,4-dinitrophenylhydrazone. Furthermore, the alkylating agent was utilized for the formation of several alpha-substituted aldehydes.