Progesterone from stigmasterol

In developing a highly efficient route from stigmasterol to progesterone (4),... 

The process for producing progesterone from soybean-derived stigmasterol is outlined in Chapter 2. 

Stigmasterol from soy bean extracts can be selectively ozonolyzed on the side-chain double bond. The 20-formyl group formed is converted to the enamine with piperidine. This can be oxidized to progesterone. 

Progesterone is a hormone, secreted by the corpus luteum, that is involved in the control of pregnancy. Its structure was established, in part, by the following synthesis from the steroid stigmasterol, obtained from soybean oil. 

It will be noted that stigmasterol also represents a commercial route to progesterone. This abundant plant sterol that is readily available from soybean with its C22-C23 double bond, easily converts to progesterone in four steps and has therefore become a preferred substrate for various steroidal drugs. Cholesterol itself, which is the natural substrate for all mammalian steroid hormones, and is readily available from various sources (e.g., wool grease), is now also convertible to desirable steroid intermediates utilizing biotransforma-tion chemistry. The same is true of P-sitosterol (Chapter 11), which is another plant sterol available from soybean. 

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