Transform functional group-keyed,

Disconnection Using Tactical Sets of Functional Group-Keyed Transforms.62... 

Functional Groups and Appendages as Keys for Connective Transforms.71... 

Aldehyde 198 served as a key intermediate in a synthesis of the alkaloid ajmaline. The. Mannich aminomethylation transform triggers disconnection of two bonds in 198 to form dialdehyde 199, which by connective transform application can be converted to cyclopentene 200.58,59 The reduction in functional group reactivity and in structural complexity are both apparent by comparison of 198 and 200. 

Photoketone (118) has served as the key intermediate in a relatively simple transformation of 3-keto-10/ -steroids to 3-keto-lOa-isomers without the assistance of other functional groups suitably situated next to the ring junction—a task that appears difficult to attempt by other methods. Optimal yields of (118) are achieved by catalytic hydrogenation of the unsaturated ketone (175), the photoisomer of 1-dehydrotestosterone acetate (see section III-C). In this way, a 6-step conversion of 1-dehydrotestosterone acetate (174) to IOa-testosterone acetate (127 acetate) is achieved in good yield. ° ... 

The nitrile group in 82 has been transformed into other versatile functional groups, and the derivatives so obtained have been used in the synthesis of various naturally occurring C-nucleosides and their analogs. Reduction of 82 with lithium aluminum hydride gave the amine 90 which was, in turn, transformed84 into the ureido and N-ni-troso derivatives (91-93) by treatment with nitrourea, followed by benzylation, and nitrosation.85 The diazo derivative 94, obtained by treatment of 93 with alcoholic potassium hydroxide, was a key intermediate in the synthesis of formycin B and oxoformycin B (see Section III,2,a,b). 

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