Pestalotiopsin a. Enantioselective construction of potential building blocks derived from antipodal cyclobutanol intermediates.
D-Glyceraldehyde acetonide has been used as the starting point for accessing the enantiomeric cyclobutanols 11 in optically pure condition. The dextrorotatory enantiomer has been transformed in five steps into the [3.2.0] bicyclic lactone 22. While the deoxygenation of 22 proved to be problematical, the uncyclized variant 25 underwent the Barton process smoothly. These findings guided the related conversion of (-)-11 into 34. Use was also made of ring-closing metathesis to bring about the conversion of (+)-11 into [4.2.0] bicyclic lactone building blocks. In general, all three pathways are efficient and offer the prospect of practical side-chain appendage for the purpose of installing the nine-membered ring of pestalotiopsin A (1).
Paquette
Leo A
LA
Evans Chemical Laboratories, The Ohio State University, Columbus, OH 43210, USA. paquette.1@osu.edu
Parker
Gregory D
GD
Tei
Takahiro
T
Dong
Shuzhi
S
D000438:Alcohols / Q000138:chemical synthesis* / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000737:chemistry; D003503:Cyclobutanes / Q000138:chemical synthesis* / Q000737:chemistry; D007783:Lactones / Q000737:chemistry; D012717:Sesquiterpenes / Q000138:chemical synthesis*; D013237:Stereoisomerism
D000438:Alcohols; D001643:Bridged Bicyclo Compounds; D003503:Cyclobutanes; D007783:Lactones; D012717:Sesquiterpenes; C430595:pestalotiopsin A