Enantioselective synthesis of (-)-terpestacin and structural revision of siccanol using catalytic stereoselective fragment couplings and macrocyclizations.
(-)-Terpestacin (1, naturally occurring enantiomer) and (+)-11-epi-terpestacin (2) were prepared using catalyst-controlled, stereoselective, intermolecular reductive coupling reactions of alkyne 9 and aldehyde 10, affording allylic alcohols 42 or 11-epi-42 in a 3:1 ratio (or 1:3 depending on the enantiomer of ligand 41a used). These stereoselective fragment couplings were instrumental in confirming that "siccanol" is not 11-epi-terpestacin but, in fact, is (-)-terpestacin itself. Several intramolecular alkyne-aldehyde reductive coupling approaches to 1 and 2 were also investigated and are discussed herein.
Massachusetts Institute of Technology, Department of Chemistry, Cambridge, Massachusetts 02139, USA.
Johann
J
Chan
Timothy F
TF
Jamison
D000447:Aldehydes / Q000737:chemistry; D000480:Alkynes / Q000737:chemistry; D001203:Ascomycota / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D012821:Silanes / Q000737:chemistry; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis
D000447:Aldehydes; D000480:Alkynes; D001643:Bridged Bicyclo Compounds; D012821:Silanes; D013729:Terpenes; C093577:fusaproliferin; C080890:terpestacin