Organozinc Reagents

Abstract

Alkylzincs were amongst the first organometallic compounds to be used in organic synthesis. However, they were rapidly superceded by the Grignard reagents which were easier to handle and more reactive. Nevertheless, they are still commonly employed in both the Reformatskii and Simmons-Smith cyclopropanation reactions and recent work on allylzinc bromides suggests that they are potentially useful precursors of olefinic compounds. Significant improvements in the generation of organozincs for these purposes have been made by employing ultrasound and a number of highly reactive species have been shown to be readily available. Luche and coworkers have published a series of papers on the conjugate addition of dialkyl and diarylzinc compounds, prepared using ultrasound, to a-enones. These latest results increase the scope for use of organozincs by demonstrating the analogies between their behaviour and the commonly used organocopper reagents.