Design, Synthesis, and 1,3-Dipolar Cycloaddition of (5<i>R</i>)- [and (5<i>S</i>)]-5,6-Dihydro-5-phenyl-2<i>H</i>-1,4-oxazin-2-one <i>N</i>-Oxides as Chiral (<i>E</i>)-Geometry-Fixed α-Alkoxycarbonylnitrones
作者:Osamu Tamura、Kentoku Gotanda、Jun Yoshino、Yasuhiro Morita、Romi Terashima、Mayumi Kikuchi、Tsutomu Miyawaki、Naka Mita、Masayuki Yamashita、Hiroyuki Ishibashi、Masanori Sakamoto
DOI:10.1021/jo000903a
日期:2000.12.1
Optically pure (5R)- [and (5S)]-5,6-dihydro-5-phenyl-2H-1, 4-oxazin-2-one N-oxides [(5R)- and (5S)-2] were designed as chiral (E)-geometry-fixed alpha-alkoxycarbonylnitrones 1. The nitrones (5R)- and (5S)-2 were synthesized by three-step oxidation of (R)- and (S)-phenylglycinols [(R)- and (S)-3], condensation of the resulting (R)- and (S)-2-hydroxylamino-2-phenylethanols [(R)- and (S)-5] with glyoxylic
光学纯的(5R)-[和(5S)]-5,6-二氢-5-苯基-2H-1、4-恶嗪-2-一N-氧化物[(5R)-和(5S)-2]为设计为手性(E)-几何固定的α-烷氧基羰基硝酮1.硝酮(5R)-和(5S)-2是通过(R)-和(S)-苯基甘氨醇[[R]-和(S)-3],将所得的(R)-和(S)-2-羟基氨基-2-苯基乙醇[[R]-和(S)-5]与乙醛酸缩合,并将中间体硝基环化(R)-和(S)-6b。硝酮(5R)-2在温和条件下与烯烃7-14反应,通过对空间要求最低的exo模式提供相应的环加合物15-22作为主要产物。从(5S)-2和环戊二烯获得的Cycloadduct 30被有效地修饰为(1S,4S,5R)-4-苄氧基羰基氨基-2-氧杂双环[3.3.0] oct-7-en-3-one(28),