Kinetic resolution of racemic tertiary allylic alcohols through SN2' reaction using a chiral bisphosphoric acid/silver(i) salt co-catalyst system.

A highly efficient kinetic resolution (KR) of racemic tertiary allylic alcohols was achieved through an intramolecular allylic substitution reaction using a co-catalyst system composed of chiral bisphosphoric acid and silver carbonate. This reaction afforded enantioenriched diene monoepoxides along with the recovery of tertiary allylic alcohols in a highly enantioselective manner, realizing an extremely high s-factor in most cases. The present method provides a new access to enantioenriched tertiary allylic alcohols, multifunctional compounds that are applicable for further synthetic manipulations.

Catalytic Enantioselective Vinylogous Allylic Alkylation of Coumarins.

An unprecedented, organocatalytic enantioselective vinylogous γ-allylic alkylation of 4-methylcoumarins has been developed. Using allylic carbonates as the allyl source, this reaction is catalyzed by Lewis basic dimeric Cinchona alkaloid (QD)2PHAL and proceeds exclusively in a γ- and branched-selective manner to produce densely functionalized coumarin derivatives generally in good yields with good to high enantioselectivities (up to 97:3 er).

Catalytic enantioselective cascade Michael/cyclization reaction of 3-isothiocyanato oxindoles with exocyclic α,ß-unsaturated ketones en route to 3,2'-pyrrolidinyl bispirooxindoles.

Cascade Michael/cyclization reactions between 3-isothiocyanato oxindoles and exocyclic α,ß-unsaturated ketones are shown to proceed efficiently in the presence of a quinine-derived tertiary amino-squaramide catalyst and furnish 3,2'-pyrrolidinyl bispirooxindoles containing two spiro-quaternary and three contiguous stereocenters as a single diastereomer with excellent enantioselectivities (up to 99 : 1 er).

Catalytic Aldol-Cyclization Cascade of 3-Isothiocyanato Oxindoles with α-Ketophosphonates for the Enantioselective Synthesis of ß-Amino-α-hydroxyphosphonates.

A cascade aldol-cyclization reaction between 3-isothiocyanato oxindoles and α-ketophosphonates has been developed for the synthesis of ß-amino-α-hydroxyphosphonate derivatives. Catalyzed by a quinine-based tertiary amino-thiourea derivative, this reaction delivers 2-thioxooxazolidinyl phosphonates based on a spirooxindole scaffold bearing two contiguous quaternary stereogenic centers in high yields with excellent diastereo- (up to >20:1 dr) and enantioselectivities (up to >99:1 er).

Catalytic asymmetric synthesis of α,ß-disubstituted α,γ-diaminophosphonic acid precursors by Michael addition of α-substituted nitrophosphonates to nitroolefins.

Michael additions of α-substituted nitrophosphonates to various nitroolefins are shown to proceed with high diastereo- and enantioselectivity when catalyzed by a quinine-derived thiourea-tertiary amine bifunctional catalyst and generate α,γ-diaminophosphonic acid precursors with contiguous quaternary and tertiary stereocenters.