A striking difference between the stereochemical course of the photolysis of 5-hydroxy 6-oxo steroids and their bicyclic analogues
✍ Scribed by Shirley Stiver; Peter Yates
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- French
- Weight
- 243 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
While 5a-and 5b-hydroxy 6-0~0 steroids undergo stereospecific photoisomerization, their bicyclic analogues give identical product mixtures on photolysis. This is attributed to equilibration of the intermediate acyl alkyl diradicals in the bicyclic case, which does not occur in the steroid case because of slowing of rotation about the C-9 -C-10 bond. We have recently discussed the stereospecific photoisomerization of the steroidal a-ketols 1 and 2 to the lactones 3 and 4, respectively, in benzene or ethanol.' We then reported that the bicyclic a-ketols 5 and 6 do not show this stereospecificity and now discuss the difference between the photochemistry of these and the steroidal a-ketols. AC