Sequential Copper‐Catalyzed Rearrangement–Allylic Substitution of Bicyclic Hydrazines with Grignard Reagents

Abstract magnified image The 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.