Synthesis and Lipase-Catalyzed Resolution of 5-(Hydroxymethyl)-1,3-dioxolan-4-ones: Masked Glycerol Analogs as Potential Building Blocks for Pharmaceuticals
作者:Robert P. Hof、Richard M. Kellogg
DOI:10.1021/jo952021v
日期:1996.1.1
(Hydroxymethyl)-1,3-dioxolan-4-ones from mandelic and lactic acids and 1,5,5-trimethyl-3-phenyloxazolidin-2-one from mandelamide were alpha-alkylated using benzyl chloromethyl ether. Reductive debenzylation of the products of alkylation unmasked the hydroxymethyl groups. The compounds obtained in this fashion were subsequently subjected to lipase-catalyzed resolution in organic media. Depending on the lipase and substrate employed, enantiomeric ratios up to E = 200 were observed. The obtained optically pure compounds can be considered as masked 2-substituted glycerol equivalents, which could be used for the preparation of tertiary (aryloxy)propanolamines, compounds having potential beta-blocking activity.
Behaviour of Dioxolanones as Chiral Acyl Anion Equivalents
作者:R. Alan Aitken、Andrew W. Thomas
DOI:10.1055/s-1998-1569
日期:1998.1
The 1,3-dioxolan-4-ones readily derived from α-hydroxy acids act as convenient acyl anion equivalents by deprotonation-alkylation followed by flash vacuum pyrolysis. Conjugate addition of their anions to ethyl crotonate similarly gives β-methyl-γ-oxo esters and by using chiral dioxolanones these can be obtained in up to 86% e.e.