Straightforward synthesis of five-membered metallacycloallenes: 1-Zirconacyclopenta-2,3-diene compounds derived from 1,3-enynes

Abstract

A five-membered metallacycloallene complex, 1-zirconacyclopenta-2,3-diene, was prepared from low-valent zirconocene and 2,4-bis(trimethylsilyl)but-1-en-3-yne. The complex reacted with carbonyl compounds to afford alkynyl alcohols after hydrolysis via C=O insertion into Zr–C bond. Similarly, nitriles inserted into the Zr–C bond to give the corresponding ketones after hydrolysis. The insertion of C=O and CN selectively took place at zirconium-sp3 carbon of the metallacycle.