Aryl radical cyclizations: One-pot syntheses of protoberberine and pavine alkaloids

Authors
Orito, K Satoh, Y Nishizawa, H Harada, R Tokuda, M
Citation
K. Orito et al., Aryl radical cyclizations: One-pot syntheses of protoberberine and pavine alkaloids, ORG LETT, 2(16), 2000, pp. 2535-2537
Citations number
26
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ORGANIC LETTERS
ISSN journal
15237060 → ACNP
Volume
2
Issue
16
Year of publication
2000
Pages
2535 - 2537
Database
ISI
SICI code
1523-7060(20000810)2:16<2535:ARCOSO>2.0.ZU;2-U
Abstract
[GRAPHICS] Treatment of 2-(2'-bromo-beta-phenethyl)isocarbostyrils 7 with AlBN-Bu3SnH in boiling benzene gave 8-oxoberbines 3 in good yields. A similar treatment of 2-(2'-bromo-beta-phenethyl)isoquinolinium bromides 6 and their nor- and homoanalogues (10, 11) induced 6-, 5-, and 7-exo radical closures in a one -pot manner to give protoberberines 2, dibenzo[b,g]indolizidine 14a and, di benzo[a,h]-1-azabicyclo[5.4.0]undecane 15a, respectively. A one-pot radical cyclization of 1(2'-bromobenzyl)isoquinoline methiodide 18a gave a pavine alkaloid, (+/-)-algemonine (19a).