Synthesis of Enantiopure 3-Azabicyclo[3.2.0]heptanes by Diastereoselective Intramolecular [2+2] Photocycloaddition Reactions on Chiral Perhydro-1,3-benzoxazines
作者:Rafael Pedrosa、Celia Andrés、Javier Nieto、Soledad del Pozo
DOI:10.1021/jo034251c
日期:2003.6.1
[2+2] photocycloadditions involving chiral 3-acryloyl-2-vinylperhydro-1,3-benzoxazines derived from (-)-8-aminomenthol are highly diastereoselective reactions. The facial selectivity depends on the type of substitution at the vinyl double bond, and always leads to cis-fused bicyclic derivatives. The de is good for compounds with one substituent at the outer carbon of the double bond at C-2, but only
[2 + 2]涉及衍生自(-)-8-氨基薄荷醇的手性3-丙烯酰基-2-乙烯基过氢-1,3-苯并恶嗪的[2 + 2]光环加成反应是高度非对映选择性反应。面部选择性取决于在乙烯基双键处的取代类型,并且总是导致顺式稠合的双环衍生物。de对于在C-2的双键的外部碳原子上具有一个取代基的化合物是有利的,但是在该位置具有两个取代基的化合物的环化中仅形成一个非对映异构体。消除薄荷醇附肢得到对映体纯的3-氮杂双环[3.2.0]庚烷。