Chiral Aluminum Catalyst System for the Enantioselective Addition of Vinylaluminum Reagents to Aldehydes: Metal Controlled Reversal of Enantioselectivity
作者:Priyanka A. Adate、Takuya Matsunaga、Hirata Shin、Toshiro Harada
DOI:10.1002/adsc.201600594
日期:2016.12.7
A chiral aluminum catalyst system has been developed for the enantioselective vinylation of aldehydes. β,β‐Disubstituted (E)‐vinylaluminum reagents, generated regio‐ and stereoselectively by the carboalumination of terminal alkynes with trimethylalumunim (Me3Al), were used straightforwardly without transmetalation to vinyltitanium reagents in the subsequent enantioselectiveaddition to aldehydes with
Processes for Highly Enantio- and Diastereoselective Synthesis of Acyclic Epoxy Alcohols and Allylic Epoxy Alcohols
申请人:Walsh Patrick
公开号:US20090163728A1
公开(公告)日:2009-06-25
The inventive subject matter relates to novel processes for making an epoxy alcohol from an aldehyde, comprising the steps of: (a) adding (i) an organozinc compound or (ii) divinylzinc compound and an diorganozinc compound to said aldehyde in the presence of a first catalyst to form an allylic alkoxide compound; and (b) epoxidizing said allylic alkoxide compound in the presence of an oxidant and a second catalyst.
A carboxylate-directed palladium-catalyzed Mizoroki–Heck alkenylation of γ,δ-unsaturated carboxylic acids with alkenyl bromides is reported. This carboxylate group is effective for chelation to a Pd center, enabling the distal alkenylation of electronically unbiased internal alkenes in the formation of conjugated 1,3-dienes with high stereoselectivity. In addition, the conjugated 1,3-diene products
An efficient Ir(III) dihydride complex catalyzed 1,3-rearrangement of allylicalcohols was realized, affording the corresponding less easily accessible allylicalcohols regio- and stereoselectively in high yields from readily available starting materials. The reaction pathway involves a π-allyl-Ir(V) intermediate and the dihydride in Ir(III) dihydride complex acts as the hydrogen switch to modulate
The 1,3-rearrangement of allylic derivatives has rarely been reported, except for allylic alcohols. Herein, we describe an iridium-catalyzed 1,3-rearrangement of readily available allylic ethers to access the difficultly prepared allylic ethers with a large steric hindrance. The developed method shows a broad substrate scope and could be used in the late-stage modification of several natural products