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Diastereoselective Route to Novel Fused or Bridged Tricyclic β‐Lactams through Intramolecular Nitrone–Alkene Cycloaddition of 2‐Azetidinone‐Tethered Alkenylaldehydes – Synthetic Applications to Carbacephams and Cyclic β‐Amino Acid Derivatives
Author(s) -
Alcaide Benito,
Sáez Elena
Publication year - 2005
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.200400792
Subject(s) - chemistry , cycloaddition , nitrone , intramolecular force , alkene , bicyclic molecule , stereochemistry , substituent , regioselectivity , lactam , stereoselectivity , combinatorial chemistry , organic chemistry , catalysis
Abstract A convenient, regio‐ and stereoselective direct route to optically pure unusually fused or bridged tricyclic β‐lactams has been developed by use of intramolecular nitrone–alkene cycloaddition (INAC) reactions of easily available monocyclic 2‐azetidinone‐tethered alkenylaldehydes as the key synthetic step. The regioselectivity of the cycloaddition can be tuned by moving the alkene substituent from N1 to C3 on the 2‐azetidinone ring. In addition, some simple, interesting transformations were tested on representative examples of the different types of tricyclic systems prepared, in order to demonstrate their potential as intermediates in the preparation of differently polyfunctionalized compounds, including carbacepham derivatives and related unconventional bicyclic systems containing medium‐sized rings fused to the β‐lactam nucleus, as well as several types of cyclic β‐amino acid derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)