Asymmetric total syntheses of (+)-coronafacic acid and (+)-coronatine, phytotoxins isolated from Pseudomonas syringae pathovars
作者:Shinji Nara、Hiroaki Toshima、Akitami Ichihara
DOI:10.1016/s0040-4020(97)00614-5
日期:1997.7
Asymmetric totalsynthesis of (+)-coronafacic acid (2), was accomplished via intramolecular 1, 6-conjugate addition as the key step. The chiral ester (+)-7 was prepared via two approaches: starting from (R)-(+)-4-acetoxy-2-cyclopenten-1-one (12), and using catalytic asymmetric Michael reactions promoted by heterobimetallic BINOL complexes. Coupling between (+)-2 and the protected coronamic acid 8 and subsequent
syntheses of four stereoisomers of coronatine employing the exo-selectiveDiels–Alder reaction as a key step. Remarkable differences in stomatal opening activity were observed between enantiomers of coronatine. This result strongly suggests that the stereo structure of coronatine is very important for its stomatal opening activity. In addition, SAR studies suggested that coronatine operates as a molecular
Asymmetric Total Syntheses of (+)-Coronafacic Acid and (+)-Coronatine
作者:Hiroaki Toshima、Shinji Nara、Akitami Ichihara
DOI:10.1271/bbb.61.752
日期:1997.1
An asymmetric total synthesis of (+)-coronafacic acid, starting from (R)-(+)-4-acetoxy-2-cyclopen-1-one as a chiral source, was accomplished. Construction of the 1-hydrindanone framework was carried out by using intramolecular 1, 6-conjugate addition as the key step. Coupling between (+)-coronafacic acid and protected coronamic acid, and subsequent deprotection provided (+)- coronatine. This is the first asymmetric total synthesis of (+)- coronatine.