AN ENANTIOSPECIFIC ENTRY TO INDOLIZIDINES BY INTRAMOLECULAR ACYLATIONOF N-PYRROLE ESTERS

Authors
JEFFORD CW THORNTON SR SIENKIEWICZ K
Citation
Cw. Jefford et al., AN ENANTIOSPECIFIC ENTRY TO INDOLIZIDINES BY INTRAMOLECULAR ACYLATIONOF N-PYRROLE ESTERS, Tetrahedron letters, 35(23), 1994, pp. 3905-3908
Citations number
14
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Tetrahedron letters → ACNP
ISSN journal
00404039
Volume
35
Issue
23
Year of publication
1994
Pages
3905 - 3908
Database
ISI
SICI code
0040-4039(1994)35:23<3905:AEETIB>2.0.ZU;2-O
Abstract
L-Glutamic diethyl ester hydrochloride was converted to its pyrrole de rivative 22 by condensation with 2,5-dimethoxytetrahydrofuran in water . Cyclization of 22 with BBr3 afforded S)-5,6-dihydro-5-ethoxycarbonyl -8(7H)-indolizinone (23). Catalytic hydrogenation of 23 over Pd/C in a cetic acid gave exclusively (5S,9R)-5-ethoxycarbonylindolizidine in an overall yield of 41%, whereas hydrogenation over Rh/Al2O3 in ethanol gave predominantly (5S,8S,9S)-5-ethoxycarbonyl-8-hydroxyindolizidine i n 48.5% overall yield.