Di-Isobornyloxyaluminium Isopropoxide—A New Highly Selective Meerwein-Ponndorf-Verley Reagent

Abstract

It has recently¹ been found that prostaglandin type ene-one intermediates can be reduced with aluminium isopropoxide. In the course of our search for a similar but more stereoselective reagent we have found that the title reagent although showing little stereo-selectivity, has distinct advantages and is a reducing agent of high practical utility. In particular this new reagent gives higher yields under milder conditions and with fewer side reactions than aluminium iso-propoxide yet it can be simply prepared from dl-isoborneol and redistilled aluminium isopropoxide by the successive removal of two moles of isopropanol as a toluene co-distillate. It is stable to dry air and is apparently indefinitely stable at room temperature in toluene solution.