Stereocontrolled synthesis of exocyclic olefins using arene tricarbonyl chromium complex-catalyzed hydrogenation. I. Efficient synthesis of carbacyclin and its analogs.

An efficient synthesis of carbacyclin and its analogs (2-7) is described in which the stereospecific 1,4-hydrogenation of a 1,3-diene to an internal monoene plays a key role. That is, arene.Cr(CO)3 complex-catalyzed 1,4-hydrogenation of the dienes 13 and 58, obtainable from the Corey lactone in good yields, under high H2 pressure afforded the exocyclic olefins 14 and 61 stereospecifically in excellent yields, and these intermediates were converted to therapeutically useful carbacyclin (2) and its analogs 3-7 in a usual way.