Routes to building blocks for heterocyclic synthesis by reduction of ketene dithioacetals
作者:John M Mellor、Stephen R Schofield、Stewart R Korn
DOI:10.1016/s0040-4020(97)10136-3
日期:1997.12
Two general methods have been developed permitting the effective reduction of ketene dithioacetals to give substituted dithianes. Reduction with magnesium in methanol is less reliable than reduction with zinc in acetic acid. The greater inconsistency of magnesium in methanol has been investigated by a cyclic voltammetric study of the substrates. The utility of the dithianes has been successfully illustrated
In the reaction of 2-ethoxy-1,3-oxathiolane with carbonylcompounds in the presence of ZnCl2 or HgCl2, it has been found that only the breaking of the endocyclic bond (C–O or C–S bond) occurs, while the breaking of the exocyclic C–O bond to give the 1,3-oxathiolan-2-ium ion is unfavorable. This behavior is different from that of 2-ethoxy-1,3-dithiolane, in which the breaking of the endocyclic C–S bond