Formal intramolecular [5+2] photocycloaddition reactions of maleimides: A novel approach to the CDE ring skeleton of (-)-cephalotaxine

Authors
Booker-Milburn, KI Dudin, LF Anson, CE Guile, SD
Citation
Ki. Booker-milburn et al., Formal intramolecular [5+2] photocycloaddition reactions of maleimides: A novel approach to the CDE ring skeleton of (-)-cephalotaxine, ORG LETT, 3(19), 2001, pp. 3005-3008
Citations number
22
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ORGANIC LETTERS
ISSN journal
15237060 → ACNP
Volume
3
Issue
19
Year of publication
2001
Pages
3005 - 3008
Database
ISI
SICI code
1523-7060(20010920)3:19<3005:FI[PRO>2.0.ZU;2-L
Abstract
[GRAPHICS] A concise approach to the cephalotaxine CDE ring skeleton based on the intr amolecular formal [5 + 2] photocycloaddition of cyclopentenyl-substituted m aleimides is described. An investigation of the diatereoselectivity afforde d by various protected alkoxy groups demonstrated that the best selectivity (3.5:1) was afforded by the free hydroxyl group, strongly suggesting a hyd rogen-bonded excited state.