Ring-opening reactions inducing molecular rearrangements

Ring-opening reactions inducing molecular rearrangements 

SCHEME 20. Partial backbone rearrangement of 22,23-methylenecholesteryl acetate (82). 

The stereochemical requirements for backbone rearrangement of the steroid framework have been well established From deuterium-labelling experiments, the energetics and conformational dynamics of intermediate tertiary cations for model decyl systems compared with the rate of adjacent proton loss and the role and mobility of counter ion in the reaction are knownThe mechanism for formation of the rearranged isomers 87, 88, 89 and 90 with both configurations at C(20) was not investigated, but epimerization at C(20) in the total backbone rearrangement of the steroid nucleus has been previously reported . 

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Ring-opening reactions inducing molecular rearrangements... 

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