Synthesis of amino allenes via reaction of α-aminoalkylcuprates with propargyl substrates

Abstract

α-Aminoalkylcuprates prepared from carbamates via sequential deprotonation and treatment with CuCN·2LiCl react with propargyl bromides, mesylates, tosylates, acetates, and epoxides to afford amino allenes via a S N2′ substitution process. Propargyl bromides and sulfonates give good yields of amino allenes while the acetates afford low yields. Substrates undergo regiospecific S N2′ substitution and the use Sc(OTf) 3 affords improved yields of amino allenes from propargyl epoxides. The Boc protected α-amino allenes can be cyclized to oxazolidones or deprotected to afford the free amines.