Preparation of Enantiomerically Pure Perfluorobutanesulfinamide and Its Application to the Asymmetric Synthesis of α-Amino Acids

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• 作者：Apiwat Wangweerawong ; Joshua R. Hummel ; Robert G. Bergman ; Jonathan A. Ellman
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：February 19, 2016
• 年：2016
• 卷：81
• 期：4
• 页码：1547-1557
• 全文大小：538K
• ISSN：1520-6904

文摘

A high yielding and practical two-step synthesis of enantiomerically pure perfluorobutanesulfinamide from Senanayake’s 2-aminoindanol-derived sulfinyl transfer reagent was developed and carried out on a multigram scale. Straightforward condensation of this sulfinamide with ethyl glyoxylate provided the N-perfluorobutanesulfinyl imino ester. The utility of this activated N-sulfinyl imino ester was demonstrated for reactions that gave either no product or very low yields with the corresponding less electrophilic N-tert-butanesulfinyl derivative. Specifically, the Rh(III)-catalyzed C–H bond addition of aromatic compounds to the N-perfluorobutanesulfinyl imino ester provided arylglycines with very high diastereoselectivities for a range of directing groups including pyrrolidine amide, azo, sulfoximine, 1-pyrazole, and 1,2,3-triazole functionalities. Thermal asymmetric aza-Diels–Alder reactions also proceeded in good yields and with high selectivity, including for the substituted dienes (E)-1,3-pentadiene and (2E,4E)-2,4-hexadiene.