Copper (II) Bromide Utilization in the Synthesis of 15-Keto-PGB₁and its 16, 16-Dimethyl Analog

Synthesis of Prostaglandin and Phytoprostane B1 Via Regioselective Intermolecular Pauson−Khand Reactions

“…It should be noted that olefination of aldehydes such as 9 and 10 was reported to be especially difficult. For example, the Wittig−Horner reaction with a keto-phosphonate gave the corresponding keto-PGB 1 in low yield . In our hands, the Wittig olefination of 10a described by Durand afforded the desired phytoprostane in low yield as a mixture of stereoisomers that were difficult to separate.…”

“…For example, the Wittig-Horner reaction with a keto-phosphonate gave the corresponding keto-PGB 1 in low yield. 18 In our hands, the Wittig olefination of 10a described by Durand afforded the desired phytoprostane in low yield as a mixture of stereoisomers that were difficult to separate. This prompted us to explore other olefination procedures to introduce the chiral side chain.…”

A Facile Route for Synthesis of (±)-Dinoprost, (±)-Carboprost and Its Analogs

“…Synthesis for dimethyl 2-oxoheptylphosphonate (8) (Scheme-I): Esterification of hexanoic acid was carried out through acid chloride preparation with thionyl chloride in dichloromethane using catalytic amount of DMF at 10-15 ºC followed by addition of methanol at 5-10 ºC for 1 h which gave 10 with 92 % yield 24,25 . Reaction of 10 with dimethyl methane phosphonate (11) in THF using n-BuLi (1.6 M in hexane) at -75 to -78 ºC for 0.5 h gave crude product which was purified by flash column chromatography to get compound 8 in 70 % yield 26,27 . During preparation of phosphonate ester (8), we have tried reactions at various temperatures such as at -40 ºC and at 0 ºC but we observed more impurities by TLC and led to lower yields after column purification.…”