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[3,3]‐Sigmatropic Rearrangement/Allylboration/Cyclization Sequence: Enantioenriched Seven‐Membered‐Ring Carbamates and Ring Contraction to Pyrrolidines
Author(s) -
Macé Aurélie,
Touchet Sabrina,
Andres Patricia,
Cossío Fernando,
Dorcet Vincent,
Carreaux François,
Carboni Bertrand
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201509824
Subject(s) - sigmatropic reaction , ring (chemistry) , chemistry , aryl , contraction (grammar) , stereochemistry , combinatorial chemistry , organic chemistry , biology , alkyl , endocrinology
The combination of in situ generated α‐isocyanato allylboronic esters and aldehydes afforded 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.