Remote or Inactive Positions

Seymour and J. M. J. Frechet, Tetrahedron Letters, 1976, 1149 and references therein. 

Photochemically labile protecting groups have also been known for several years newly described indolenine derivatives (24) of acids give back the acid when photolysed in water, but give the amide in the presence of ammonia. There has been a review of the electrochemical removal of protecting groups.  

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Remote or Inactive Positions.—Breslow and his co-workers have sought to mimic some aspects of enzyme behaviour in other ways, and have published a full paper on remote halogenation of steroids, giving various partial syntheses [e.g. cortexolone (24) to dihydrocortisone (25)] they have extended the principle to remote epoxida-tion. The reiterative functionalization process of Watt has also been applied in the steroid field, providing activation at C-18, and aimed eventually at preparing aldosterone. 

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