Pivaloyl linkers

FIGURE 7.3 Oligosaccharides synthesized by automation using octenediol or butenediol linkers and the major milestones achieved. Piv, pivaloyl TCA, trichloroacetyl. 

Amide-modified farnesylcysteine (AMFC) analogs were synthesized and evalnated as snbstrates or inhibitors of the methyltransferase. Acyl substitutions bearing small alkyl groups are substrates however, a pivaloyl-FC derivative has neither substrate nor inhibitor activity. A benzolyl-FC series was also investigated and similarly lacked activity however, introducing a flexible linker between the benzolyl and FC groups restored substrate activity. These data indicate that bulky substitutions at the amine group of the FC are not well tolerated by the enzyme. 

Scheme 17.17 Incorporation of the pivaloyl motif in the photolabile linker 34 and subsequent use in the solid phase synthesis of alcohols.

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