Synthesis of Allylboronates via Zweifel‐type Deprotonative Olefination

Abstract

A method for the synthesis of allylboronates via Zweifel‐type deprotonative olefination was demonstrated. Tetrasubstituted vinylboronates were used as the substrates. NCS (N‐chlorosuccinimide) was used as a bifunctional additive, electrophile and base. This method exhibited a different elimination strategy in Zweifel type transformation to afford allylboronates. The homo‐alcohols and alkenes were stereoselective synthesized from the obtained allylboronates, demonstrating the synthetic value of this methodology.

Recent Progress on the Zweifel Olefination: An Update

“…This method features a different elimination strategy for the Zweifel-type olefination that can afford allylboronate products, which can be further transformed into many other valuable compounds (Scheme 8 ). 11…”

“…This method features a different elimination strategy for the Zweifel-type olefination that can afford allylboronate products, which can be further transformed into many other valuable compounds (Scheme 8). 11 Besides 1,2-migration of alkenyl tetracoordinate boron complexes, other unsaturated systems, for example, their alkynyl analogues, could also undergo 1,2-migration under activation with appropriate electrophiles. However, in previously reported cases, only one phenyl group of the triphenyl-substituted tetracoordinate boron species could participate in migration, thus resulting in a low functionality utilization ratio of the tetracoordinate boron substrates.…”

3-Silyl-3-Borylhex-4-Enoate: A Chiral Reagent for Asymmetric Crotylboration of Aldehydes

“…The corresponding products possessing a stereodefined trisubstituted vinylsilane could be further functionalized by decoration of the R group, increasing the structural complexity in a rapid and diverse manner. However, 1,1-disubstituted silyl allylborons have been barely studied and utilized in asymmetric synthesis because of their poor accessibility. First, it is difficult to enantioselectively construct the sterically demanding quaternary carbon bearing both bulky silyl and boryl groups.…”