Premium
A New Three‐Component Cascade Reaction to Yield 3‐Spirocyclopropanatedβ‐Lactams
Author(s) -
Zanobini Alessandra,
Brandi Alberto,
de Meijere Armin
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200500838
Subject(s) - chemistry , yield (engineering) , alkyl , ethanol , formaldehyde , carboxylate , acetylation , organic chemistry , block (permutation group theory) , medicinal chemistry , materials science , geometry , mathematics , metallurgy , biochemistry , gene
A one‐pot three‐component reaction for the direct conversion of certain alkylhydroxylamine hydrochlorides 8 (alkyl = benzyl, p ‐methoxybenzyl, benzhydryl, tert ‐butyl), formaldehyde ( 9 ) or an alkyl glyoxylate ( 10 ) and bicyclopropylidene ( 2 ) to furnish 3‐spirocyclopropanated 2‐azetidinones 7 , 11 has been developed. Microwave heating of mixtures of the three components in the presence of sodium acetate in ethanol for 15–120 min furnished the products 7 , 11 in 49–78 % yield (7 examples). A new protocol for the oxidative deprotection of the 3‐spirocyclopropanated methyl 1‐( p ‐methoxybenzyl)‐2‐carboxylate 11b ‐Me provides the β‐lactam building block 17 ‐Me in 90 % yield, and the latter can be reprotected and activated with an N‐tert ‐butoxycarbonyl (Boc) group in 82 % yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)