1,5-dioxaspiro[3.2]hexanes and 4-oxaspiro[2.3]hexanes as templates for novel nucleosides

Date of Completion

January 2005


Chemistry, Organic




The utility of 1,5-dioxaspiro[3.2]hexanes as organic templates is described. It had previously been demonstrated that these systems displayed a dichotomy of reactivity, which generated α-functionalized-β-hydroxy ketones or 2,2-disubstituted oxetanes. Control over this dual reactivity was further investigated using nitrogen-based heteroaromatic nucleophiles. Regioselective control to provide substituted oxetanes was accomplished via formation of Lewis acid induced oxonium ion intermediates. The utility of 2,2-disubstituted oxetane products was soon demonstrated in the synthesis of a new class of nucleoside analogs, psico-nucleosides. Herein, we discuss the versatility of 1,5-dioxaspiro[3.2]hexanes as templates for the preparation of nucleoside analogs. ^ Another approach to the synthesis of psico-nucleoside analogs via platinum(II)-catalyzed opening of 4-oxaspiro[2.3]hexanes is also described. The unexpected results of the ring opening and a proposed pathway of reactivity are later discussed. ^