Organic Synthesis Using Haloboration Reaction. XXI. A Synthesis of Prostaglandin B<sub>1</sub>Methyl Ester by the Stepwise Cross-Coupling Reaction Using (<i>E</i>)-(2-Bromoethenyl)diisopropoxyborane
作者:Satoshi Hyuga、Shoji Kara、Akira Suzuki
DOI:10.1246/bcsj.65.2303
日期:1992.8
A prostaglandin B1(PGB1) analog and PGB1 methyl ester were synthesized by the palladium-catalyzed stepwise cross-coupling reaction of (E)-(2-bromoethenyl)diisopropoxyborane with (1-methoxy-1-hexenyl)zinc chloride and 3-bromo-2-cyclopenten-1-one derivatives. According to this method, the skeleton of PGB1 is prepared by the one-pot operation without isolation of any intermediates.
3-(Dimethoxyphosphorylmethyl)cyclopent-2-enone was converted into (+/-)-prostaglandin B1 methyl ester in two steps involving regioselective alkylation at C(2) with methyl 7-iodoheptanoate and subsequent Horner-Wittig reaction with dimer of 2-hydroxyheptanal (42% overall yield). The use of (R)- and (S)-2-(tert-butyldimethylsilyloxy)heptanal for the Horner olefination reaction gave, after deprotection