Lewis acid mediated diastereoselective keto-ene cyclization on chiral perhydro-1,3-benzoxazines: synthesis of enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines
摘要:
Chiral 2-acyl-3-allyl-perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol were easily cyclized in the presence of Lewis acids at 0 degrees C. The diastereoselectivity of the cyclization was dependent on the nature of the Lewis acid. The cyclization compounds can be transformed into enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines by ring opening of the N,O-acetal moiety and subsequent elimination of the menthol appendage. (C) 2009 Elsevier Ltd. All rights reserved.
Lewis acid mediated diastereoselective keto-ene cyclization on chiral perhydro-1,3-benzoxazines: synthesis of enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines
摘要:
Chiral 2-acyl-3-allyl-perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol were easily cyclized in the presence of Lewis acids at 0 degrees C. The diastereoselectivity of the cyclization was dependent on the nature of the Lewis acid. The cyclization compounds can be transformed into enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines by ring opening of the N,O-acetal moiety and subsequent elimination of the menthol appendage. (C) 2009 Elsevier Ltd. All rights reserved.
Lewis acid mediated diastereoselective keto-ene cyclization on chiral perhydro-1,3-benzoxazines: synthesis of enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines
作者:Celia Andrés、Israel González、Javier Nieto、Carlos D. Rosón
DOI:10.1016/j.tet.2009.09.091
日期:2009.11
Chiral 2-acyl-3-allyl-perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol were easily cyclized in the presence of Lewis acids at 0 degrees C. The diastereoselectivity of the cyclization was dependent on the nature of the Lewis acid. The cyclization compounds can be transformed into enantiopure cis-3,4-disubstituted 3-hydroxypyrrolidines by ring opening of the N,O-acetal moiety and subsequent elimination of the menthol appendage. (C) 2009 Elsevier Ltd. All rights reserved.