Abstractmagnified imageThe problem of the synthesis of trans‐1,4‐disubstituted hydrazino‐ and aminocyclopentenes has been resolved by a sequential copper‐catalyzed rearrangement–allylic alkylation of 2,3‐diazabicyclo[2.2.1]heptenes. The cis‐fused 5,5‐membered allylic carbazate which is formed in situ by a novel copper(II) triflate [Cu(OTf)2]/(±)‐BINAP‐catalyzed rearrangement, can be alkylated with a broad spectrum of Grignard reagents with a predominant SN2′‐regioselectivity. The N‐Boc protecting group proved to be optimal as regards yields, reaction times and regioselectivities.
Regio- and Stereoselective Copper-Catalyzed Ring Opening of Diheterobicyclic Alkenes with Grignard Reagents
作者:Mauro Pineschi、Stefano Crotti、Valeria Di Bussolo
DOI:10.1055/s-0031-1290821
日期:2012.5
opening of bicyclic hydrazines and bicyclic oxazines with organomagnesium reagents under the influence of copper catalysts allows functionalized cyclopentene and cyclohexene derivatives to be obtained. Whereas complete anti-stereoselective ring opening occurred in all cases, the regioselective outcome turned out to be highly dependent on the reaction conditions used. The ring opening of bicyclic hydrazines