Synthesis 2011(5): 723-730  
DOI: 10.1055/s-0030-1259485
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Synthesis of 3-Alkoxy/Aryloxy-β-lactams Using Diazoacetate Esters as Ketene Precursors Under Photoirradiation

Hengzhen Qi, Zhanhui Yang, Jiaxi Xu*
State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, Faculty of Science, Beijing University of Chemical Technology, Beijing 100029, P. R. of China
Fax: +86(10)64435565; e-Mail: jxxu@mail.buct.edu.cn;
Further Information

Publication History

Received 29 November 2010
Publication Date:
03 February 2011 (online)

Abstract

3-Alkoxy/aryloxy-β-lactams are synthesized in satisfactory to good yields from the reaction of imines and alkyl/aryl di­azoacetates under photoirradiation conditions. Typically, trans-β-lactams are obtained as the major products from linear imines using the current method. By contrast, the corresponding thermal reaction of imines and alkoxy/aryloxyacetyl chlorides, or their equivalents, in the presence of triethylamine affords cis-β-lactams as the major or exclusive products. The formation of trans-β-lactams from linear imines is attributed to isomerization of the imines from their trans-isomers into syn-isomers under UV irradiation. The reported method represents a metal-free and neutral approach for the synthesis of 3-alkoxy/aryloxy-β-lactams.