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

Article abstract of DOI:10.1016/S0040-4039(99)00778-9

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(N)2' substitution process. Propargyl bromides and sulfonates give good yields of amino allenes while the acetates afford low yields. Substrates undergo regiospecific S(N)2' 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.