Upjohn prostaglandin synthesis

The Pfizer process to latanoprost starts with the Corey aldehyde benzoate (13, CAB), available as a relatively stable crystalline solid via the historic Upjohn prostaglandin synthesis (Scheme 3).17 The reaction of the phosphonate with CAB (13) is done using... 

The synthetic route to the prostaglandins developed by Kelly and his colleagues at Upjohn similarly depends on a rigid polycyclic framework for establishment of the stereochemistry. The synthesis differs significantly from that above in that a rearrangement step is used to attain the stage comparable to 23. 

Prostacyclin (8, 256-257). The Upjohn synthesis of prostacyclin has been described in detail. The key step, iodination of prostaglandin F2. methyl ester, is greatly improved by use of I2 and KI rather than I2 alone. The paper also reports synthesis of the related prostaglandin Ii (5,6-dihydroprostacyclin), prostaglandin I3 (derived from prostaglandin p3 ), and 6-ketoprostaglandin Fi , the hydrolysis product of prostacyclin. ... 

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