Synthesis 2019; 51(21): 4106-4112
DOI: 10.1055/s-0039-1690150
paper
© Georg Thieme Verlag Stuttgart · New York

Evaluation of Amino Nitriles and an Amino Imidate as Organo­catalysts in Aldol Reactions

Nikolaos Vagkidis
,
Alexander J. Brown
,
Department of Chemistry, University of York, Heslington, York YO10 5DD, North Yorks, UK   Email: paul.clarke@york.ac.uk
› Author Affiliations
We thank the Department of Chemistry, The University of York for financial support.
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Publication History

Received: 13 June 2019

Accepted after revision: 18 July 2019

Publication Date:
08 August 2019 (online)


Abstract

The efficiency of l-valine and l-proline nitriles and a tert-butyl­ l-proline imidate as organocatalysts for the aldol reaction have been evaluated. l-Valine nitrile was found to be a syn-selective catalyst, while l-proline nitrile was found to be anti-selective, and gave products in modest to good enantioselectivities. tert-Butyl l-proline imidate was found to be a very efficient catalyst in terms of conversion of starting reagents to products, and gave good anti-selectivity. The enantioselectivity of the tert-butyl l-proline imidate was found to be good to excellent, with products being formed in up to 94% enantiomeric excess.

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