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

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 S_N2′ product 7 was produced using dichloromethane as a solvent and triethylamine (7 equiv) as base; S_N2 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

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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.