Development of chiral heteroleptic magnesium amides; asymmetric deprotonations mediated by six-membered metallocyclic amidomagnesium naphtholates
作者:Emma L. Carswell、William J. Kerr、Duncan McArthur、Marek Pažický、Allan J.B. Watson
DOI:10.1016/j.tet.2014.06.052
日期:2014.10
A series of enantioenriched six-membered metallocyclic amidomagnesium naphtholates were prepared and used to probe the structure-reactivity/selectivity relationships of heteroleptic magnesium base complexes within asymmetric deprotonation reactions. An effective complex was identified and applied within enantioselective enolisation processes, delivering good levels of enantioselectivity and also revealing key structural requirements for achieving such selectivity. (C) 2014 Elsevier Ltd. All rights reserved.
Solvent-Free Asymmetric Aminoalkylation of Electron-Rich Aromatic Compounds: Stereoselective Synthesis of Aminoalkylnaphthols by Crystallization-Induced Asymmetric Transformation
Electron-rich aromatic compounds such as 2-naphthol give a faster and asymmetric 1-aminoalkylation with high yields when treated with (R)-1-phenylethylamine and aromatic aldehydes in solvent-free conditions. An asymmetric transformation of a second kind, probably induced by the preferential crystallization of one diastereomer, affords the straightforward and stereoselective synthesis of aminoalkylnaphthols. Mechanisms predictable for this asymmetric reaction are reported. The absolute configurations and the conformations of the unknown aminonaphthols are widely ascertained.