Aziridination of cyclic dienes with enantiopure 3-acetoxyaminoquinazolin-4(3H)-ones
作者:Robert S. Atkinson、Christopher K. Meades
DOI:10.1039/b102592a
日期:——
Aziridination of cyclopentadiene and cyclohepta-1,3-diene with (S)-3-acetoxyamino-2-(3-hydroxy-2,2-dimethylpropyl)quinazolin-4(3H)-one 6 (Q1NHOAc) in the presence of titanium(IV) tert-butoxide in dichloromethane takes place highly diastereoselectively: X-ray structure determinations show that the preferred sense of diastereoselectivity in both cases is the same as that previously found for aziridination of butadiene with 6. Aziridination of cyclohexa-1,3-diene with 6 was less diastereoselective in dichloromethane solution but highly diastereoselective in acetonitrile: in this solvent two diastereoisomeric cis-4-(Q1-amino)cyclohexen-3-ols 27 and 28 were also obtained as by-products. The same two amino
alcohols were obtained by ring-opening of the aziridine with acid and were each converted into Q1-free oxazolidinones having optical rotations which were similar in magnitude but opposite in sign.
环戊二烯和环七烯-1,3-二烯与(S)-3-乙酸氧氨基-2-(3-羟基-2,2-二甲基丙基)喹唑啉-4(3H)-酮6 (Q1NHOAc) 在四氧化钛和二氯甲烷的存在下发生了高的非对映选择性:X射线结构分析显示,两种情况下的非对映选择性偏好与之前发现的对丁二烯与6的非对映选择性一致。环己烯-1,3-二烯与6的环化反应在二氯甲烷溶液中表现出较低的非对映选择性,但在乙腈中则表现出高度的非对映选择性:在这种溶剂中还获得了两个非对映异构体的顺式-4-(Q1-氨基)环己烯-3-醇27和28作为副产物。这两个氨醇通过酸催化环戊烯开环也获得,并被转化为不含Q1的噁唑烷酮,且它们的光旋度在大小上相似但符号相反。