Cyclopropanation of tricarbonyl(styrene)chromium(0)and (–)- Ar(1R,2S)-tricarbonyl[2-(trimethylsilyl)styrene] chromium(0)

Abstract

Addition of the lithium anion of isobutyronitrile and iodomethane to (–)-Ar(1R, 2S)-tricarbonyl[2-(trimethylsilyl)styrene]chromium(0)(–)-2′ gave (–)-Ar(1R, 2S)-tricarbonyl{(4S)-2,2-dimethyl-4-[2-(trimethylsilyl)phenyl}pentanenitrile}chromium(0)(–)-6, the stereochemistry of which was determined by an X-ray crystallographic analysis. Tricarbonyl(styrene)chromium(0) 5 and (–)-Ar(1R,2S)-tricarbonyl[2-(trimethylsilyl)styrene]chromium(0)(–)2′ reacted with sulfur and phosphorus ylides, and α-chloro organometallics to give tricarbonylchromium(0) complexes of mono-, di- and tri-substituted cyclopropanes. The stereochemistry of one of the products, (–)-Ar(1R, 2S)-tricarbonyl{(1S,2S)-trans-1-methoxy-2-[2-(trimethylsilyl)phenyl]cyclopropane}chromium(0)(–)-18 was determined by an X-ray crystallographic analysis. Desilylation of (–)-18 proceeded smoothly to give (–)-tricarbonyl (1S,2S)-trans-1-methoxy-2-phenylcyclopropane]chromium(0)(–)-11.