[3,3]-Sigmatropic Rearrangement/Allylboration/Cyclization Sequence: Enantioenriched Seven-Membered-Ring Carbamates and Ring Contraction to Pyrrolidines

Aurélie Macé (1) , Sabrina Touchet (1) , Patricia Andres , Fernando Cossío , Vincent Dorcet (1) , François Carreaux (1) , Bertrand Carboni (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

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

Mots clés: allylic compounds; asymmetric synthesis; Heterocycles; reaction mechanisms; rearrangements

Domaines: Chimie

Aurélie Macé, Sabrina Touchet, Patricia Andres, Fernando Cossío, Vincent Dorcet, et al.. [3,3]-Sigmatropic Rearrangement/Allylboration/Cyclization Sequence: Enantioenriched Seven-Membered-Ring Carbamates and Ring Contraction to Pyrrolidines. Angewandte Chemie, 2016, 55 (3), pp.1025-1029 ⟨10.1002/anie.201509824⟩. ⟨hal-01240655⟩