Synthesis of the syributins and formal total synthesis of syringolide 1

A synthesis of syributins 1 (5) and 2 (6) from D-glyceraldehyde acetonide (12) and furans (14) and (15) is described. Compounds (5) and (6) are cometabolites of the novel non-proteinaceous C-glycosidic elicitor molecules the syringolides 1 (1) and 2 (2). Under a variety of acidic conditions, the intermediate butenolides (9) and (10) provided syributins 1 (5) and 2 (6). Similar results have been reported by Honda and coworkers who converted butenolide (20) into syringolide 1 (1). Since compound (20) was also synthesized by the present new route, a formal synthesis of syringolide 1 (1) has been achieved.