A Zwitterionic Carbanion Frustrated by Boranes - Dihydrogen Cleavage with Weak Lewis Acids via an Inverse Frustrated Lewis Pair Approach

The synthesis, structural characterization, and acid base chemistry of [C(SiMe2OCH2CH2OMe)(3)] Na (2), a sterically encumbered zwitterionic organosodium compound, is reported. 2 is a strong Bronsted base that forms frustrated Lewis pairs (FLPs) with a number of boron-containing Lewis acids ranging from weakly Lewis acidic aryl and alkyl boranes to various alkyl borates. These intermolecular FLPs readily cleave H-2, which confirms that even poor Lewis acids can engage in FLP-mediated H-2 cleavage provided that the present bulky base is of sufficiently high Bronsted basicity.