[3,3]-Sigmatropic Rearrangement/Allylboration/Cyclization Sequence: Enantioenriched Seven-Membered-Ring Carbamates and Ring Contraction to Pyrrolidines
作者:Aurélie Macé、Sabrina Touchet、Patricia Andres、Fernando Cossío、Vincent Dorcet、François Carreaux、Bertrand Carboni
DOI:10.1002/anie.201509824
日期:2016.1.18
seven‐membered‐ring enecarbamates with high levels of diastereo‐ and enantiocontrol. They were easily converted into diversely substituted 1,3‐oxazepan‐2‐ones. An unprecedented rearrangement of 5‐acetoxy‐7‐aryl or styryl derivatives led to tetrasubstituted pyrrolidines. A computational study provides evidence on the feasibility of the proposed mechanism of this unusual ring contraction.
原位生成的α-异氰酸根合烯丙基硼酸酯和醛的结合提供了具有高水平的非对映和对映体控制的七元环烯氨基甲酸酯。它们很容易转化为各种取代的1,3-氧杂氮杂-2-酮。5-乙酰氧基-7-芳基或苯乙烯基衍生物的前所未有的重排导致四取代的吡咯烷。一项计算研究为这种异常环收缩的拟议机制的可行性提供了证据。