Unravelling the stereoselectivity in 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars. A tale of two stereocenters.
A computational investigation on the origin of the stereoselectivity of 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars has revealed that a boat-like transition state, which keeps the ester in a planar conformation, holds the chiral information. Following this model, the stereocenter to which the ester functionality is connected reports the chirality to the newly formed stereocenter via a 1,4-transfer mechanism.
Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, UFMG, 31270-901, Belo Horizonte, MG, Brazil. mtavares@netuno.lcc.ufmg.br
Marcelo T
MT
de Oliveira
Amary
A
Cesar
Daniel H S
DH
Leal
Maria A F
MA
Prado
Thais H A
TH
da Silva
Ricardo J
RJ
Alves
D002241:Carbohydrates / Q000737:chemistry*; D003500:Cyclization; D004952:Esters / Q000737:chemistry; D008958:Models, Molecular; D013237:Stereoisomerism
D002241:Carbohydrates; D004952:Esters