A PRACTICAL METHOD FOR ACTIVATION OF COMMERCIAL LITHIUM HYDRIDE - REDUCTIVE SILYLATION OF CARBONYL-COMPOUNDS WITH LITHIUM HYDRIDE AND CHLOROTRIMETHYLSILANE

Commercially available lithium hydride, an essentially inert metal hyd ride, can be activated as a hydride source by an equimolar amount of c hlorotrimethylsilane and a catalytic amount of a Zn salt or Zn powder. Aromatic and aliphatic ketones, as well as nonenolizable aldehydes, a re reductively converted to the trimethylsilyl ethers of the correspon ding alcohols in high yields by treatment with this reagent system in dichloromethane or toluene at 28 to 40 degrees C for 25-50 h. This pro cedure has many advantages including the safety and low cost of the re agents and operational simplicity and provides a practical method for carbonyl reduction. X-ray induced Auger electron spectroscopy analysis suggests that a Zn(II)I species is the catalyst of the heterogeneous reaction.