Diastereoselective yang photocyclization reactions in solution. synthesis of enantiopure azetidin-3-ol derivatives.
[reaction: see text] Chiral 2-acyl-3-allyl- or 2-acyl-3-benzyl-substituted perhydro-1,3-benzoxazines readily cyclized under irradiation to azetidin-3-ol derivatives. The diastereoselectivity of the cyclization is dependent on the nature of the substituents at the nitrogen atom. N-allyl-substituted derivatives yielded only two of the four possible diastereomers in moderate to good diastereomeric excess. The cyclization of N-benzyl derivatives was totally diastereoselective leading to a single diastereomer. The elimination of the menthol appendage lead to enantiopure 2,3-disubstituted azetidin-3-ol derivatives.
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
Nieto
Javier
J
del Pozo
Soledad
S