Total synthesis of (+)-allocyathin B2.
The first enantioselective synthesis of (+)-allocyathin was achieved. The synthesis features a Pd-catalyzed asymmetric allylic alkylation to install the first quaternary center, a Ru-catalyzed diastereoselective cycloisomerization to construct the six-membered ring, and a diastereoselective hydroxylative Knoevenagel reaction to introduce the final hydroxyl group. The unusual olefin isomerization of the Ru-catalyzed cycloisomerization was discussed and exploited for the synthesis.
Trost
Barry M
BM
Department of Chemistry, Stanford University, Stanford, California 94301-5080, USA.
Dong
Li
L
Schroeder
Gretchen M
GM
D000478:Alkylation; D003500:Cyclization; D004224:Diterpenes / Q000138:chemical synthesis*; D010165:Palladium / Q000737:chemistry; D011083:Polycyclic Compounds / Q000138:chemical synthesis*
D004224:Diterpenes; D011083:Polycyclic Compounds; C430643:allocyathin B2; D010165:Palladium