Total syntheses of (+)- and (-)-pestalotiopsin A.
An enantioselective total synthesis of both enantiomers of caryophyllene-type sesquiterpenoid pestalotiopsin A has been achieved, thereby establishing the absolute stereochemistry of natural (+)-pestalotiopsin A. Highlights of the synthesis include a [2 + 2] cycloaddition of N-propioloyl Oppolzer's camphorsultam and ketene dialkyl acetal and subsequent highly stereoselective 1,4-hydride addition/protonation, an aldol reaction of functionalized bicyclic lactone with aldehyde, an efficient intramolecular Nozaki-Hiyama-Kishi (NHK) reaction for the construction of the highly strained (E)-cyclononene ring, and a palladium-catalyzed reduction of allylic mesylate with retention of the E configuration.
Takao
Ken-ichi
K
Department of Applied Chemistry, Keio University, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. takao@applc.keio.ac.jp
Hayakawa
Nobuhiko
N
Yamada
Reo
R
Yamaguchi
Taro
T
Saegusa
Hiroshi
H
Uchida
Masatoshi
M
Samejima
Suguru
S
Tadano
Kin-ichi
K
D000447:Aldehydes / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D003500:Cyclization; D020128:Inhibitory Concentration 50; D007783:Lactones / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014961:X-Ray Diffraction
D000447:Aldehydes; D007783:Lactones; D012717:Sesquiterpenes; C430595:pestalotiopsin A; D010165:Palladium; C116609:3-hydroxybutanal