Enantioselective Syntheses of Syributin 1 and Novel C-Glycosidic Elicitors Syringolides 1 and 2

摘要: Concise enantioselective syntheses of syributin 1 (3) and the novel nonproteinaceous C-glycosidic elicitors syringolides 2 (1 2, respectively), isolated from Pseudomonas syringae pv. tomato, are described. Syributin was synthesized in one step by Sharpless catalytic asymmetric dihydroxylation (AD reaction) (1‘E)-3-(3‘-(octanoyloxy)-1‘-propenyl)but-2-en-4-olide (13) 72% yield with >98% ee. Furthermore, alkylation (1‘R,2‘R)-3-[1‘-(tert-butyldimethylsiloxy)-2‘,3‘-(isopropylidenedioxy)propyl]but-2-en-4-olide (20), prepared (1‘E)-3-[3‘-(tert-butyldimethylsiloxy)-1‘-propenyl]but-2-en-4-olide (11) AD reaction, hexanal or octanal Jefford's procedure at α position to lactone carbonyl group gave adduct 21 22 good yield. Oxidation 22, followed removal protecting groups, provided syringolide respectively.