Towards Simplifying the Chemistry of N-Acyliminium Ions: A One-Pot Protocol for the Preparation of 5-Acetoxy Pyrrolidin-2-ones and 2-Acetoxy N-Alkoxycarbonyl Pyrrolidines from Imides

Abstract

A new one-step protocol for the synthesis of acetoxy lactams starting from imides has been developed. This method involves regiospecific reduction of the imide with LiEt₃BH, then capture of the transient lithium alkoxide by acetic anhydride.

Key words

N-acyliminium ion precursors - imide reduction - LiEt₃BH - one-pot process

References

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18

Compounds 5d and 5e were prepared from (S)- and (R)-pyroglutamic acid using typical procedures for functional-group transformations similar to those employed for 5a-c.

19

The yield of 2b fell to 63% when 5 g of 1b was used (the corresponding hydroxy lactam was also isolated in 16% yield) and to 40% when the reaction was carried out on a 7.5 g scale.