Ti(II)-mediated conversion of α-heterosubstituted (O, N, S) nitriles to functionalized cyclopropylamines.: Effect of chelation on the cyclopropanation step

alpha-Alkoxy, amino-, and thio nitriles under-go a Ti(II)-mediated coupling with Grignard reagents to afford heterofunctionalized cyclopropylamines. A chelation effect appears to be generally responsible for the spontaneous contraction of the intermediate azatitanacycle leading to cyclopropane. By using the described reaction, 1-amino-cyclopropanecarboxylic acids were prepared in four steps, in good overall yields, from the readily available benzyloxy-acetonitrile.