Diastereoselective Additions of Titanium Enolates from N-Glycolyl Thiazolidinethiones to Acetals

作者:Baiget Jessica; Caba Marta; Galvez Erik; Romea Pedro*; Urpi Felix; Font Bardia Merce
来源:Journal of Organic Chemistry, 2012, 77(19): 8809-8814.
DOI:10.1021/jo301569x

摘要

The stereochemical outcome of the Lewis acid-mediated glycolate addition of the titanium enolates from protected N-hydroxyacetyl-4-isopropyl-1,3-thiazolidine-2-thiones to dimethyl and dibenzyl acetals depends on the hydroxyl protecting group. Particularly, the pivaloyl protected glycolate derivative provides the reluctant anti adducts in high yields and diastereomeric ratios, which can be isolated and further converted in enantiomerically pure form to beta-methoxy or beta-benzyloxy alpha-pivaloyloxy carbonyl fragments in a straightforward manner.

  • 出版日期2012-10-5