Ti(II)-mediated conversion of alpha-heterosubstituted (O, N, S) nitriles to functionalized cyclopropylamines. Effect of chelation on the cyclopropanation step.
Alpha-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.
Bertus
Philippe
P
Réactions Sélectives et Applications, CNRS, and Université de Reims, 51687 Reims Cedex 2, France.
Szymoniak
Jan
J