Selective Metal-free HB(C6 F5 )2 Catalyzed Allene Cyclotrimerization: Formation of 1,3,5-Trimethylenecyclohexane and Its Tris-hydroboration Product.

Abstract

Allene is cyclotrimerized under metal-free conditions with the borane HB(C6 F5 )2 catalyst to selectively give 1,3,5-trimethylenecyclohexane (3 a). Three-fold hydroboration of the 1,3,5-cyclotrimer with Piers' borane gives the all-cis 1,3,5-CH2 B(C6 F5 )2 substituted cyclohexane product 14.