Ti(II)-Mediated Conversion of α-Heterosubstituted (O, N, S) Nitriles to Functionalized Cyclopropylamines. Effect of Chelation on the Cyclopropanation Step

α-Alkoxy, amino-, and thio nitriles undergo 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-aminocyclopropanecarboxylic acids were prepared in four steps, in good overall yields, from the readily available benzyloxyacetonitrile.