Ene Reaction of Singlet Oxygen, Triazolinedione, and Nitrosoarene with Chiral Deuterium-Labeled Allylic Alcohols: The Interdependence of Diastereoselectivity and Regioselectivity Discloses Mechanistic Insights into the Hydroxy-Group Directivity
作者:Waldemar Adam、Nils Bottke、Oliver Krebs、Ioannis Lykakis、Michael Orfanopoulos、Manolis Stratakis
DOI:10.1021/ja027800p
日期:2002.12.1
The ene reaction of singlet oxygen ((1)O(2)), triazolinedione (TAD), and nitrosoarene, specifically 4-nitronitrosobenzene (ArNO), with the tetrasubstituted 1,3-allylically strained, chiral allylic alcohol 3,4-dimethylpent-3-en-2-ol (2) leads to the threo-configured ene products in high diastereoselectivity, a consequence of the hydroxy-group directivity. Hydrogen bonding favors formation of the threo-configured
单线态氧 ((1)O(2))、三唑啉二酮 (TAD) 和亚硝基芳烃,特别是 4-亚硝基苯 (ArNO) 与四取代的 1,3-烯丙基张力、手性烯丙醇 3,4-二甲基戊的烯反应-3-en-2-ol (2) 导致具有高非对映选择性的苏式构型的烯产物,这是羟基方向性的结果。氢键有利于在烯反应的早期形成苏式构型的遭遇复杂的苏式-EC。对于类似的 twix 氘标记的烯丙醇 Z-2-d(3),在四取代醇的区域选择性中公开了 (1)O(2) 与 ArNO 和 TAD 亲烯体之间迄今尚未认识到的二分法:而对于 ArNO 和TAD,与烯丙基羟基的氢键决定了区域选择性(twix 选择性),对于(1)O(2),顺式效应占主导地位(孪生/三重选择性)。从双/双区域选择性和苏/赤非对映选择性之间的相互依赖性,已经认识到,亲烯体也可以在没有与烯丙基羟基官能团的氢键帮助的情况下从赤π面攻击烯丙醇。