Copper(I)tert-Butoxide-Promoted 1,4 C^sp2-to-O Silyl Migration:  Generation of Vinyl Copper Equivalents and Their Stereospecific Cross-Coupling with Allylic, Aryl, and Vinylic Halides

Abstract

Successive treatment of the (Z)-gamma-trimethylsilyl allylic alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammonium fluoride-assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration. Similar treatment of the organometallic intermediates with aryl and vinylic halides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective preparation of the starting materials is also described.

Silicon-based cross-coupling reaction: an environmentally benign version

“…49 Indeed, efficient transmetalation of alkenyl(trimethyl)silanes with copper(I) has been demonstrated by Takeda and coworkers: a palladium-catalysed cross-coupling reaction occurs with the aid of a proximal hydroxy group (eqn (30)). 50 A similar effect using a carboxylate group has also been reported by Shindo and coworkers (eqn (31)). 51…”

Palladium-catalysed cross-coupling of organosilicon reagents

“…Alkenyl-and aryl(trimethyl)silanes having a proximal hydroxyl group were found to undergo transmetallation from silicon to copper upon treatment with copper(I) tert-butoxide; the resulting copper species then underwent palladium-catalysed crosscoupling with aryl iodides. 46,47 A drawback of these examples is that one of groups present in the products (i.e. a transferable group on the silicon) is always the oxygen-based activating functionality.…”

A synthesis of strychnine by a longest linear sequence of six steps

“…2c, 4 A brief discussion of the D-ring-forming step is in order. 14,15 This specific type of Brook rearrangement finds precedent in the work of Takeda 16 and more recently in the anion-relay chemistry of Smith. 17 While these workers report many examples of highyielding C-C bond formations after the initial rearrangement, our substantial efforts in optimization 18 led to the best case as shown in Scheme 3.…”