Abbreviated synthesis of the C3-C14 (substituted 1,7-dioxaspiro[5.5]undec-3-ene) system of okadaic acid.
[formula: see text] Described is a novel, concise, and flexible synthesis of the C3-C14 portion of okadaic acid. A substituted valerolactone (C3-C8) was prepared in three steps and alpha-hydroxylated using Davis' oxaziridine. Conjugate addition of dimethylcuprate upon ynones derived from the C3-C8 lactones followed by intramolecular ketalization provided the C3-C14 fragment and revealed a significant role of the C7 alpha'-ketone substituent upon the efficiency of spiroketalization.
Dounay
A B
AB
Department of Chemistry, University of Minnesota, Minneapolis 55455, USA.
Forsyth
C J
CJ
D000475:Alkenes / Q000138:chemical synthesis*; D004791:Enzyme Inhibitors / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis; D019319:Okadaic Acid / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis*
C410132:1,7-dioxaspiro(5,5)undec-3-ene; D000475:Alkenes; D004791:Enzyme Inhibitors; D007783:Lactones; D013141:Spiro Compounds; D019319:Okadaic Acid