Concise syntheses of coronarin A, coronarin E, austrochaparol and pacovatinin A.
Total syntheses of (+)-coronarin A (1), (+)-coronarin E (2), (+)-austrochaparol (3) and (+)-pacovatinin A (4) were achieved from the synthetic (+)-albicanyl acetate (6). Dess-Martin oxidation of (+)-albicanol (5) derived from the chemoenzymatic product (6) gave an aldehyde (7), which was subjected to Julia one-pot olefination using beta-furylmethyl-heteroaromatic sulfones (8 or 9 ) gave (+)-trans coronarin E (2) and (+)-cis coronarin E (12) with high cis-selectivity. The synthesis of (+)-coronarin A (1) from (+)-trans coronarin E (2) was achiev-ed, while (+)-cis coronarin E (12) was converted to the natural products (+)-(5S,9S,10S)-15,16-epoxy-8(17),13(16),14-labdatriene (13) and (+)-austrochaparol (3). By the asymmetric synthesis of (+)-3, the absolute structure of (+)-3 was determined to be 5S, 7R, 9R, 10S configurations. Homologation of (+)-albicanol (5) followed by allylic oxidation gave (7 alpha)-hydroxy nitrile (17), which was finally converted to the natural (+)-pacovatinin A (4) in 8 steps from (+)-albicanol (5).
Miyake
Takahiro
T
Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Uda
Keisuke
K
Kinoshita
Masako
M
Fujii
Mikio
M
Akita
Hiroyuki
H
D000447:Aldehydes / Q000737:chemistry; D004224:Diterpenes / Q000138:chemical synthesis*; D005663:Furans / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009281:Naphthalenes / Q000138:chemical synthesis*; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D030521:Zingiberaceae / Q000737:chemistry
D000447:Aldehydes; D004224:Diterpenes; D005663:Furans; D007202:Indicators and Reagents; D009281:Naphthalenes; C528529:austrochaparol; C481378:coronarin A; C482830:coronarin E; C436803:pacovatinin A