Total syntheses of cladoacetals A and B: confirmation of absolute configurations.
The first enantioselective syntheses of cladoacetals A (1a, overall yield: 16%) and B (1b, overall yield: 34%) from crotonaldehyde in nine and seven steps, respectively, have been accomplished. Sharpless asymmetric dihydroxylation, Suzuki coupling, and acid-catalyzed intramolecular acetalization were the key steps in the syntheses. The absolute configuration of natural (+)-cladoacetal A was affirmed to be 1S,3S,4R, whereas that of (-)-cladoacetal B was affirmed to be 1R,3S,4S.
Department of Chemistry and Biochemistry, National Chung Cheng University, Minhsiung, Taiwan 621. chedsh@ccu.edu.tw
Day-Shin
DS
Hsu
Shih-Chung
SC
Lin
D000447:Aldehydes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006575:Heterocyclic Compounds, 3-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
D000447:Aldehydes; D006575:Heterocyclic Compounds, 3-Ring; C576307:cladoacetal A; C576308:cladoacetal B; C012796:2-butenal