Synthesis 2019; 51(17): 3356-3368
DOI: 10.1055/s-0037-1611531
paper
© Georg Thieme Verlag Stuttgart · New York

l-Prolinal Dithioacetal: A Highly Effective Organocatalyst for the Direct Nitro-Michael Addition to Selected Cyclic and Aromatic Ketones

Piotr Pomarański
,
Zbigniew Czarnocki*
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Publication History

Received: 19 February 2019

Accepted after revision: 05 April 2019

Publication Date:
02 May 2019 (online)


Abstract

The synthesis of novel l-prolinal dithioacetal and its application as an organocatalyst for the direct Michael addition of cyclic ketones and acetophenone derivatives to trans-β-nitrostyrene and related compounds is described. The prolinal dithioacetal acts as effective catalyst in the case of cyclic ketones of different ring size, in particular five- and six-membered examples, as well as larger and smaller ring systems. High enantioselectivity and diastereoselectivity is observed for different substrates and trans-β-nitrostyrenes. Also, the first asymmetric syntheses of selected 2-methyl-4-nitro-1,3-diphenylbutan-1-one derivatives by application of the obtained organocatalyst is presented.

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