Impact of Catalyst Deuteration on the Reactivity of Chiral Phase-Transfer Organocatalysts
Sei Murayama1, Zhurong Li2,3, Huatai Liang2,3
1Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan.
Abstract:
Site-specifically deuterated organocatalysts were prepared and found to show improved reactivity over the non-deuterated analogs. Two privileged C2 -symmetric chiral binaphthyl-modified tetraalkylammonium salts were selected for this study. The stability of these phase-transfer catalysts was generally improved by site-specific deuteration, though the degree of improvement was structure dependent. In particular, a large secondary kinetic isotope effect was observed for the tetradeuterated phase-transfer catalyst. The performance of these deuterated catalysts in the asymmetric catalytic alkylation of amino acid derivatives was better than that of non-deuterated analogs at low catalyst loadings. The results suggest that catalyst deuteration is a promising strategy for enhancing the stability and performance of organocatalysts.
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