Oxidative Cyclization of Sulfamate
Esters Using NaOCl - A Metal-Mediated Hoffman-Löffler-Freytag
Reaction
作者:J. Du Bois、David Zalatan
DOI:10.1055/s-0028-1087392
日期:——
Intramolecular C-H amination with sulfamate esters occurs under the action of dinuclear Rh catalysts and iodine(III) oxidants, and has recently emerged as a powerful tool for synthesis. Insights gained through mechanistic studies of this process suggest that other terminal oxidants, including common halogenating agents such as NaOCl, could function to promote the cyclization reaction. Results described in this report demonstrate that the combination of NaOCl and 3 mol% Rh2(oct)4 is effective in select cases for converting sulfamate substrates to the corresponding [1,2,3]-oxathiazinane-2,2-dioxide heterocycles. The mechanism for C-H functionalization, however, is distinct from that induced by hypervalent iodine reagents and likely involves the intermediacy of an N-centered radical.
在双核 Rh 催化剂和碘(III)氧化剂的作用下,氨基磺酸酯会发生分子内 C-H 氨化反应,最近已成为一种强大的合成工具。对这一过程的机理研究表明,其他末端氧化剂(包括 NaOCl 等常见卤化剂)也能促进环化反应。本报告中描述的结果表明,NaOCl 和 3 mol% Rh2(oct)4 的组合在某些情况下能有效地将氨基磺酸盐底物转化为相应的 [1,2,3]-氧硫杂嗪烷-2,2-二氧化物杂环。不过,C-H 功能化的机理与超价碘试剂诱导的机理不同,可能涉及 N-中心自由基的中间产物。