Temperature- and time-dependent stereochemical control in thermally induced keto-ene cyclizations.
Reaction conditions determine the stereoselection in the intramolecular keto-ene reaction. The thermolysis of chiral 2-acyl-3-allyl-substituted 1,3-perhydrobenzoxazines derived from (-)-8-aminomenthol gives a mixture of only two cis-3-hydroxy-3,4-disubstituted pyrrolidine nuclei. The stereochemistry of the major diastereoisomer depends on both the temperature and the reaction time.
Pedrosa
Rafael
R
Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Valladolid, Dr. Mergelina s/n, 47011-Valladolid, Spain. pedrosa@qo.uva.es
Andrés
Celia
C
Rosón
Carlos D
CD
Vicente
Martina
M