deprotonation of β-hydroxynitriles with MeMgCl (2.1 equiv.) generates a dianion that ejects MgO to provide the corresponding α,β-unsaturatednitriles. Structurally diverse β-hydroxynitriles readily eliminate MgO providing an expedient route to highly substituted α,β-unsaturatednitriles.
The SmI2-mediated coupling of alpha-bromoacetonitrile and alpha-bromopropionitrile with aliphatic ketones and aldehydes produces beta-hydroxynitriles in good yields. Reactions typically proceed with little diastereoselectivity, but selectivity enhancement occurs with the addition of tetra-n-hexylammonium bromide. (C) 2000 Elsevier Science Ltd. All rights reserved.