SYNTHESIS OF A MARINE POLYETHER TOXIN, OKADAIC ACID (4).TOTAL SYNTHESIS.

Article abstract of DOI:10.1016/S0040-4020(01)86918-0

Three segments A, B and C for okadaic acid synthesis were coupled with each other in order of A+(B+C), the key steps of the twice couplings being between sulfone carbanions and aldehydes.After the B+C coupling , the asymmetric center C-27 was generated by a hydride reduction of the corresponding ketone 16 under electronic control.The second coupling was followed to form the C-14/15 double bond.Oxidation of the α-oxy aldehyde 36 into the carboxylic acid group was achieved with sodium chlorite without C-1/C-2 bond cleavage.The total synthesis of okadaic acid was accomplished in 106 steps from commercially available D-glucose derivative s and butyne-diol.