Designer Lewis acid based on molecular recognition

Abstract

A Lewis acid is an excellent candidate as a proton substitute in man-made organic reactions. The observation that organoaluminum compounds immediately ignite when exposed to air, a reflection of the high affinity of aluminum for oxygen, inspired us to devise a new series of reagents based on that metal. Our goal was to engineer an artificial proton of a special shape, which could be utilized as an effective tool for chemical reactions, by harnessing the high reactivity of the aluminum atom towards oxygen. Such a concept was initially researched by examining the influence of a specially designed organometallic reagent on a typical organic reaction. The successful diastereoface discrimination observed in the alcohol synthesis induced us to examine the more intricate question of enantioface differentiation. Creation of new chirality in a product molecule requires the use of a chiral catalyst. Therefore, an investigation was launched to determine whether a chiral Lewis acid could possibly achieve the desired result.