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Synlett 2005(13): 2035-2038  
DOI: 10.1055/s-2005-871934
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of β-Amino Esters by Regioselective Amination of Allyl Bromides with Aryl and Alkyl Amines

Hung-Yang Chena, Laxmikant N. Patkarb, Shau-Hua Uengb, Chun-Cheng Lin*b,c, Adam Shih-Yuan Lee*a
a Department of Chemistry, Tamkang University, Tamsui, Taiwan
b Institute of Chemistry and Genomic Research Center, Academia Sinica, Taipei, Taiwan
c Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan
Fax: +88(62)26223830; e-Mail: adamlee@mail.tku.edu.tw;
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Publication History

Received 1 June 2005
Publication Date:
07 July 2005 (online)

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Abstract

One of the two possible regioisomers can be exclusively formed by combining a suitable solvent and a specific amount of triethylamine as a base during the amination of allyl bromide 5. The SN2′ product 7 was produced using dichloromethane as a solvent and triethylamine (7 equiv) as base; SN2 product 6 was predominantly generated in hexane with 0.5 equivalents of triethylamine. Furthermore, a new reaction condition for the efficient cyclization of 7 to yield α-methylene β-lactam 8 using Sn[N(TMS)2]2 as a ­reagent, is disclosed.

Key words

β-amino ester - amination - regioselectivity - α-methylene β-lactam - allyl bromide

14

In the case of benzylamine addition to the allyl bromide 2 with ester substituent at C-2 position, 38% yield was afforded.

15

As indicated in ref. 12a, the reaction products with alkyl amines are heat-labile oils, which decompose on Florisil or silica gel during column purification.