In the presence of HX, carbanions Mes2BCHLiR1 react with aliphatic aldehydes to give alkenes. The stereochemistry of the product alkene depends upon the nature of HX.
The stereochemistry of the reactions between tris(2-methoxy-methoxyphenyl)phosphonioethanide (1f), -butanide (2f), and -phenyl-methanide (3f) and a variety of aldehydes was investigated. Ylides having a β-unbranched aliphatic sidechain, such as 2f, and saturated straight-chain aldehydes give olefins with unprecedented cis-selectivity (cis/trans â 200:1).
Hindered organoboron groups in organic synthesis. 13. The direct production of ketones from aliphatic aldehydes by a unique variant of the boron-wittig reaction
Vinylic organoboranes. 9. A general stereospecific synthesis of (Z)- and (E)-disubstituted alkenes via organoboranes
作者:Herbert C. Brown、Deevi Basavaiah、Surendra U. Kulkarni、Narayan G. Bhat、J. V. N. Vara Prasad
DOI:10.1021/jo00237a003
日期:1988.1
A general and stereospecific synthesis of cis alkenes via stepwise hydroboration: a simple synthesis of muscalure, the sex pheromone of house fly (Musca domestica)