Intramolecular [4+2] cycloaddition of a photogenerated o-quinone methide in aqueous solution

被引：25

作者：

Barker, B ^{[1
]}

Diao, L ^{[1
]}

Wan, P ^{[1
]}

机构：

[1] UNIV VICTORIA,DEPT CHEM,VICTORIA,BC V8W 3V6,CANADA

来源：

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY | 1997年 / 104卷 / 1-3期

基金：

加拿大自然科学与工程研究理事会;

关键词：

intramolecular [4 + 2] cycloaddition; phenol photodissociation; quinone methide;

D O I：

10.1016/S1010-6030(96)04535-2

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Using an appropriately substituted o-hydroxybenzyl alcohol precursor 5, it is shown that a photogenerated o-quinone methide can undergo efficient intramolecular [4 + 2] (Diels-Alder) cycloaddition in aqueous CH3CN solution at 15 degrees C, to generate the hexahydrocannabinol ring system 11. The dienophile tether must be sufficiently electron rich, having at least three alkyl groups. Laser flash photolysis studies show the intermediacy of an o-quinone methide (h(max) approximate to 400 nm) which has a lifetime > 2 ms. Quantum yields for reaction and fluorescence parameters are also reported which depend strongly on the proportion of water in the H2O-CH3CN solvent mixture. (C) 1997 Elsevier Science S.A.

引用

页码：91 / 96

页数：6

共 24 条

[1] ORTHO-QUINONE METHIDES .2. STEREOSELECTIVITY IN CYCLO-ADDITION REACTIONS OF ORTHO-QUINONE METHIDES WITH VINYL ETHERS [J].