Copper(I)-Mediated Regio- and Stereoselective Allylic Substitutions and Their Applications to Natural Product Syntheses

This work focused on the copper(I)-mediated stereoselective anti-allylic substitution reactions using organozinc reagents and chiral cyclic phosphates or pentafluorobenzoates. The applications of this method to the preparation of natural products were also reported

Recent Progress in Steroid Synthesis Triggered by the Emergence of New Catalytic Methods

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154510/1/ejoc201901466_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154510/2/ejoc201901466.pd

SN2' alkylation of chiral allylic cyanohydrin o-phosphates with organocuprates

Enantiomerically enriched cyanohydrin O-phosphates, prepared by enantioselective cyanophosphorylation of α,β-unsaturated aldehydes, react regioselectively at the γ-position with organocuprates derived from alkyl Grignard reagents and CuCN to afford chiral γ-alkyl-substituted α,β-unsaturated nitriles. The configuration of the new C–C double bond is mainly (E) when the reaction is performed at –78 °C and (Z) when it is carried out at higher temperatures (0 °C). A high level of transfer of the chirality in the new stereocentre, corresponding to a stereospecific anti attack onto the cyanophosphate, is observed. Enantiomerically enriched (E)-γ-alkylated α,β-unsaturated esters are prepared after subsequent methanolysis in a three-step sequence from the corresponding α,β-unsaturated aldehydes. In addition, the synthesis of (R)-4-methylnonan-1-ol, also known as the sex pheromone of the yellow mealworm Tenebrio molitor L, and its (S) enantiomer have been carried out in a four-step route from (E)-oct-2-enal.This work has been supported by the DGES of the Spanish Ministerio de Educación y Ciencia (MEC) (CTQ2004-00808/BQU), the Generalitat Valenciana (CTIOIB/2002/320, GRUPOS03/134 and GV05/144) and the University of Alicante