Switchable Regioselective 7-endo or 6-exo Iodocyclization of O-Homoallyl Benzimidates

Abstract

We present a facile switchable regioselective 7-endo or 6-exo iodocyclization of O-homoallyl benzimidates here, which affords various iodo-substituted 1,3-oxazines and tetrahydro-1,3-oxazepines in a controllable manner. The products can further undergo substitution reactions to afford a series of rich functionalized target heterocyclic molecules. The developed protocol has the advantages of mild conditions, simple operation, and excellent functional group compatibility.

Recent Progress in N-Iodosuccinimide (NIS)-Mediated Iodination Reactions

“…随后, 王力竞课题组 [56] 进一步发展了 NIS 促进的苯 甲酰亚胺高烯丙酯的区域选择性 7-endo 或 6-exo 亲电串 联碘环化反应, 以可控的方式合成了各种碘取代的 1,3-噁嗪和四氢-1,3-噁氮杂䓬类化合物(Scheme 36). 这些产 物可以进一步发生取代反应, 得到一系列具有丰富官能 团的杂环物质.…”

Synthesis of 1,3‐oxazepine derivatives via tandem reaction of 5‐benzylidine Meldrum's acids with TosMIC in presence of potassium carbonate

“…He and co-workers obtained new 1,3-oxazepines by reacting O-homoallyl benzimidates (4) with Togni reagent [5]. In another study, tetrahydro-1,-3-oxazepine derivatives (6), which are 7-endoiodocyclisation products, were obtained by reacting O-homoallyl benzimidates (4) in the presence of Niodosuccinimide (NIS) [6]. Orelli and co-workers synthesized tetrahydro-1,3-oxazepines (8) by microwaveassisted cyclization of N-benzoyl-4-aminobutanol (7) in solvent-free medium in the presence of trimethylsilyl polyphosphate [7].…”