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The functional group migration strategy could facilitate the construction of complex structures from relatively simple starting materials.

Transfer Methylenation: A copper-catalyzed transfer methylenation via the cleavage of unstrained C(sp3)-C(sp3) bonds is developted. This is a de novo report for transfer hydrocarbylation between alcohols and carbonyl compounds.

2-Pyridinylmethyl Borrowing: Transition-metal-free 2-pyridinylmethyl borrowing C-alkylation of alcohols access to ketones is developed. This unstrained C(sp3)–C(sp3) bonds cleavage of unactivated alcohols avoids the use of transition metals.

A regio- and chemoselective sulfonylation of propargyl alcohols with sulfinamides in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) was developed. It provided straightforward and mild access to multi-substituted allenyl sulfones by using sulfinamides as the sulfonyl sources. This transformation was promoted by HFIP and did not require any catalysts or oxidants, which allowed for the successful conversion of various tertiary and secondary propargyl alcohols into allenyl sulfones in high yields.

The isomerization of allylic alcohols to the corresponding carbonyl compounds is a well-established reaction in organic synthesis. However, 1,3-carbon migration is a quite challenging field, and thus transformation has remained elusive until now. Herein, we present the ruthenium-catalyzed intramolecular 1,3-aryl migrative isomerization, which provides a mild and environmentally friendly method to synthesize various ketones with high step- and atom-economy and broad substrate scope. Meanwhile, the Ru(III)-catalyzed C(sp

Carbon migration of alkenyl alcohols has been recognized as an increasingly viable methodology in organic synthesis. Herein, we disclose a silver-catalyzed 1,3-aza-benzyl migration of allyl alcohols by utilizing chelation-assisted selective cleavage of an unstrained C(sp

The semipinacol rearrangement of allylic alcohols and their derivatives via a three-membered chloronium intermediate is a well-established procedure for the synthesis of vinyl chlorides. Herein, we report a new mix-and-go general procedure involving chlorocyclization/cycloreversion of allylic alcohols with N-chlorobenzenesulfonimide (NCSI), affording remote carbonyl vinyl chlorides. This procedure proceeds through a three-membered chloronium intermediate, which chlorocyclizes to form oxetane, and then catalyst-free cycloreversion takes place under mild reaction conditions with broad functional group tolerance and good to excellent yields.

A novel approach of transition-metal-free cyano 1,3-migration of β,γ- and α,β-unsaturated cyanohydrins is reported. This method provides reliable and convenient access to β-cyano ketones in high yields. Furthermore, it has broad substrate scope and good functional group tolerance and could be scaled-up. Mechanistic study revealed that DBU plays three roles in this system, serving as a base as well as catalyzing hydride transfer and the addition of the cyano moiety to the unsaturated ketone intermediate.

A highly regioselective and catalyst-free sulfonation of allylic alcohols with sulfinyl amides has been realized. Such a mix-and-go procedure provides a convenient approach to synthetically various allylic sulfones under mild reaction conditions. Furthermore, this novel reaction shows ample substrate scope and outstanding functional group tolerance and could also be scaled-up. Meanwhile, it is the first example that sulfinyl amides act as a powerful sulfur nucleophile in the reactions. 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP) as a solvent plays a critical role in allylic sulfonation.

A direct nickel-catalyzed, high atom- and step-economical reaction of cyanohydrins with aldehydes or ketones via an unprecedented “cyano-borrowing reaction” has been developed. Cleavage of the C–CN bond of cyanohydrins followed by aldol condensation and conjugate addition of cyanide to α,β-unsaturated ketones proceeded to deliver a range of racemic β-cyano ketones with good to high yields. The practical procedure with the use of a commercial and less-toxic CN source bodes well for wide application of this protocol.

We present herein an unprecedented enantioselective isomerization of homoallylic and bishomoallylic secondary alcohols, catalyzed by a commercially available rhodium-complex and a base. This catalytic redox-neutral process provides an effective access to chiral ketones in high efficiency and enantioselectivity, without the use of any stoichiometric reagent or generation of any waste. For the reaction of homoallylic alcohols, this system achieved not only a stereoconvergent access to chiral ketones bearing a β-stereocenter (up to 95%, 86% ee) but also a concomitant oxidative kinetic resolution of the alcohol substrates (S > 20). In the case of bishomoallylic alcohols, an intriguing ligand-induced divergent reactivity was observed. A terminal-to-internal alkene isomerization promoted by Rh/L7 followed by redox isomerization using Rh/BINAP system produced chiral ketones bearing a γ-stereocenter with high yield and enantioselectivity. Mechanistic studies provided strong support for the redox-isomerization pathway with chain walking of the key alkyl-Rh intermediate.

The direct amination of cyanohydrins with amines via a catalytic cyano-borrowing reaction was developed. The transformation features broad substrate scope, excellent functional group compatibility, and very mild and simple operations. Moreover, a titanium catalyst supported by quinine and (S)-BINOL ligands enabled an asymmetric cyano-borrowing reaction with moderate to high enantioselectivity.

We report herein the first enantioselective cycloaddition of vinyl oxetanes, the reaction of which with azadienes provided unprecedented access to ten-membered heterocycles through a [6+4] cycloaddition. By using a commercially available chiral Pd-SIPHOX catalyst, a wide range of benzofuran- as well as indole-fused heterocycles could be accessed in excellent yield and enantioselectivity. A unique Lewis acid induced fragmentation of these ten-membered heterocycles was also discovered.

Fixed-bed sorption technology is a promising option for separating CO2 from flue gas, and potassium-based Al2O3 (K2CO3/Al2O3) is a potential sorbent in the presence of H2O. This paper studies the stepwise reaction mechanism of CO2/H2O sorption on K2CO3/Al2O3, and the expressions of sorption equilibrium and kinetics are proposed and verified by experimental data. A comprehensive set of mathematical models of separation and recovery CO2 from wet flue gas in a fixed bed of K2CO3/Al2O3 is established. The CO2 separation and recovery process from wet flue gas in the fixed bed are numerically studied. Detailed results of H2O/CO2 sorption and desorption in the fixed bed during pressure/vacuum swing cycles are revealed, and the optimum operating parameters are suggested. Results show that carbon dioxide recovery can be further enhanced using a vacuum temperature swing adsorption (VTSA) process or by adding a pre-wetting step before sorption process.

An efficient copper(I)-catalyzed one-pot domino reaction for the (Z)-selective construction of diazabicyclo[5.3.0]decatriene derivatives under mild conditions has been developed. This protocol was initiated by a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), followed by a ring opening rearrangement and then subsequent higher-order [8+2] cycloaddition of azaheptafulvene with ketenimine intermediates at the corresponding C-2 and N-3 sites, affording biologically active heterocycles in good to high yields.

The first catalytic enantioselective isomerization of secondary allylic alcohols to access ketones with a α-tertiary stereocenter is presented. The racemic allylic alcohol substrates can be converted to the enantioenriched ketone products in a stereoconvergent fashion. The use of commercially available catalysts and mild reaction conditions makes this an attractive method in stereoselective synthesis.

An unconventional cleavage of an unstrained carbon–carbon bond in allylic alcohols can be induced by the use of N-fluorobenzenesulfonimide (NFSI) under catalyst-free conditions. By using this simple procedure, a wide range of functionalized Z-fluoroalkenes can be accessed in high yield and selectivity from cyclic and acyclic allylic alcohols.

α-Aminonitrile was an important building block in natural products and key intermedia in organic chemistry. Herein, the direct amination of cyanohydrins with the partner of ammonia to synthesis N-unprotected α-aminonitriles is developed. The reaction proceeds via titanium-catalyzed cyano-borrowing reaction, which features high atom economy and simple operation. A broad range of ketone or aldehyde cyanohydrins was tolerated with ammonia, and the N-unprotected α-aminonitriles were synthesis with moderate to high yields under mild reaction conditions.

Bioactive 5-aza-spiro[2,4]heptanes with high functionality and up to three contiguous all-carbon quaternary stereogenic centers were synthesized by Cu(I)-catalyzed asymmetric endo-selective 1,3-dipolar cycloaddition of azomethine ylides with cyclopropylidene acetates. This synthesis system performs well for a broad scope of substrates. α-unsubstituted/α-substituted azomethine ylides and cyclopropylidene acetates are compatible 1,3-dipoles and dipolarophiles, which afford the spiro heterocycles with contiguous quaternary centers at 2-, 3- and 4-positions of the pyrrolidine ring in good yield (up to 97%) and high diastereoselectivity (95:5–>98:2 d.r) and excellent enantioselectivity (87%–98% ee).

A novel method to desymmetrize meso-anhydrides into lactones via asymmetric hydrogenation catalyzed by the Ir-C3*-TunePhos complex has been developed. Various chiral lactones were synthesized with full conversion and excellent enantioselectivity under high reaction temperature.

The high enantioselective rhodium-catalyzed hydroformylation of 1,1-disubstituted allylphthalimides has been developed. By employing chiral ligand 1,2-bis[(2S,5S)-2,5-diphenylphospholano]ethane [(S,S)-Ph-BPE], a series of β3-aminoaldehydes can be prepared with up to 95% enantioselectivity. This asymmetric procedure provides an efficient alternative route to prepare chiral β3-amino acids and alcohols.

Facile access to enantioenriched isoindolines bearing a quaternary stereogenic center and a tertiary stereogenic center was successfully developed via highly efficient Cu(I)/(S,Rp)-PPFOMe-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide with quinone derivatives followed by silica-gel-promoted aromatization in a one-pot reaction protocol. The present catalytic system exhibited high diastereoselectivity, excellent enantioselectivity, and a broad substrate scope under mild conditions.

Pyrrole into one: The catalytic asymmetric 1,3-dipolar cycloaddition of cyclic aldimino esters has been accomplished for the first time, enabling facile access to spiro(butyrolactonepyrrolidines) containing one spiro quaternary center and three tertiary stereogenic centers (see scheme). The catalytic system performs well with a broad range of substrates, furnishing synthetically useful adducts in high yields, with excellent diastereo- and enantioselectivities under mild conditions.

The first catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides with various sterically hindered α,α,β-trisubstituted 2-alkylidene-cycloketones has been developed successfully with silver acetate/TF-BiphamPhos complex for the construction of spiro heterocyclic compounds containing pyrrolidine motifs and a spiro quaternary stereogenic carbon center. The highly efficient catalytic system exhibited high reactivity, excellent diastereoselectivity, good enantioselectivity and broad substrate scope under mild conditions. Subsequent transformations led to the expedient preparation of synthetically useful spiro[pyrrolidine-tetrahydropyranone] and spiro[pyrrolidine-isochroman-1-one] without loss of the diastereo- and enantiomeric excesses.

Mild conditions, broad substrate scope, and the commercially available Rh-DuanPhos catalyst are features of this hydrogenation.

Highly regioselective and enantioselective asymmetric hydrogenation of cyclic dienamides catalyzed by an Rh-DuanPhos complex has been developed, which provides a readily accessible method for the synthesis of chiral cyclic allylic amines in excellent enantioselectivities (up to 99% ee). The products are valuable chiral building blocks and could be easily transformed to multisubstituted cyclohexane derivatives.

An expedient access to almost enantiopure spiro compounds (III) and (V) via an unprecedented Cu-catalyzed 1,3-dipolar cycloaddition is developed.

The high enantioselective rhodium-catalyzed hydroformylation of 1,1-disubstituted allylphthalimides has been developed. By employing chiral ligand 1,2-bis[(2S,5S)-2,5-diphenylphospholano]ethane [(S,S)-Ph-BPE], a series of β3-aminoaldehydes can be prepared with up to 95% enantioselectivity. This asymmetric procedure provides an efficient alternative route to prepare chiral β3-amino acids and alcohols.

The catalyst system allows the preparation of various derivatives in a diastereoselective manner with high enantioselectivities.

Catalytic asymmetric cycloaddition of cyclic aldimino esters is accomplished for the first time, providing facile access to spiro(butyrolactone-pyrrolidines) containing one spiro quaternary center and three tertiary stereogenic centers.

The catalytic system under investigation exhibits high reactivity, excellent diastereoselectivity, good enantioselectivity and a broad substrate scope under mild conditions allowing direct access to spirocyclic chromanones with a quaternary and three tertiary stereogenic centers.

Conditions A) including AgOAc in combination with the chiral biphenyl ligand are effective for substrates derived from cyclopentanone.

A facile synthesis of highly functional spiro-[4-chromanone-3,3′-pyrrolidine] bearing one unique spiro quarternary and three tertiary stereogenic centers is developed in excellent stereoselectivity for the first time.

A simple, efficient, and stereoselective method to prepare biologically important spirooxindole-pyrrolidines like (III) is reported.

A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed viacatalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.

A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.

The first exo-selective asymmetric 1,3-dipolar cycloaddition of alkylidene malonates with azomethine ylides catalyzed by AgOAc/TF-BiphamPhos has been reported in good yields and good to excellent enantio-/diastereoselectivities.

An expedient access to optically active spiro-[butyrolactone-pyrrolidine] was successfully developed via an unprecedented Cu(I)-catalyzed exo-selective 1,3-DC of azomethine ylides with α-methylene-γ-butyrolactone, which exhibited high diastereoselectivity (>98 : 2), excellent enantioselectivity (96–>99% ee) and a broad substrate scope under mild conditions.

Asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene with azomethine ylides for the construction of spirooxindole-pyrrolidines bearing four contiguous stereogenic centers has been achieved with AgOAc/TF-BiphamPhos complexes for the first time. This catalytic system performance well over a broad scope of substrates, providing the synthetically useful adducts in high yields and excellent diastereoselectivities and moderate enantioselectivities.

The first exo-selective asymmetric 1,3-dipolar cycloaddition of alkylidene malonates with azomethine ylides catalyzed by AgOAc/TF-BiphamPhos has been reported in good yields and good to excellent enantio-/diastereoselectivities.