Asymmetric catalysis. Production of chiral diols by enantioselective catalytic intramolecular hydrosilation of olefins

Abstract

Rhodium(1) chiral diphosphine complexes efficiently and rapidly catalyze the intramolecular hydrosilation of silyl
\nethers derived from allylic alcohols. The efficiency and rates of intramolecular hydrosilations were determined for a variety
\nof silyl and olefin substituents. The catalysts were found to tolerate a wide variety of silyl substituents, although terminal
\nalkyl olefin substituents were found to retard catalysis. Terminal aryl olefin substituents were found to be hydrosilated efficiently
\nand at reasonable rates. One of the chiral catalysts is highly enantioselective for terminal aryl olefin substituents. Almost
\nquantitative eels are obtained. Moreover, the ee’s are only slightly sensitive to aryl and olefin substituents, suggesting that
\nthis enantioselective catalysis can provide a wide range of chiral species. Oxidative cleavage of the hydrosilation products
\ngives chiral diols.