Synthesis of indolizine derivatives and their related compounds using ketene dithioacetals.

The synthesis of indolizine derivatives and their related compounds using ketene dithioacetals is described. This review is concerned with following five items : 1) the 1, 5-dipolar cyclization ; 2) the reaction of picolinium salts with ketene dithioacetals ; 3) the reaction of 2-pyridyl ketene dithioacetals with α-halocarbonyl compounds ; 4) the reaction of pyridinium or isoquinolinium ketene dithioacetals ; 5) the reaction of N-imines or S-imine with ketene dithioacetals.