CC BY-ND-NC 4.0 · Synthesis 2019; 51(05): 1253-1262
DOI: 10.1055/s-0037-1611657
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Lewis Acid Promoted Trapping of Chiral Aza-enolates

Francesco Lanza
,
Juana M. Pérez
,
Ravindra P. Jumde
,
Stratingh Institute for Chemistry, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands   Email: s.harutyunyan@rug.nl
› Author Affiliations
Financial support from NWO (Vidi and ECHO to S.R.H.) and the Ministry of Education, Culture and Science (Gravity programme 024.001.035 to S.R.H.) is acknowledged. J.M.P. thanks the European Commission for an Intra-European Marie Curie fellowship (grant 746011–ChirPyr).
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Publication History

Received: 07 December 2018

Accepted after revision: 17 December 2018

Publication Date:
29 January 2019 (online)


Published as part of the 50 Years SYNTHESIS – Golden Anniversary Issue

Abstract

We present a study on sequential conjugate addition of ­Grignard reagents to alkenyl-heteroarenes followed by trapping of the resulting enolates, yielding moderate to good diastereoselectivities. Contrary to conventional wisdom, one-pot conjugate addition/trapping using two reactive Michael acceptors in combination with Grignard reagents can proceed via conjugate addition to the least reactive Michael acceptor. This unusual chemoselectivity is triggered by the presence of a Lewis acid, reverting the usual reactivity order of Michael acceptors.

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