Protecting/radical-translocating groups

Aryl Radicals Protecting/Radical-Translocating Groups 263... 

Scheme 28. or / (9-(Bromoaryldimethylsilyl) protective/radical-translocating groups... 

S.3 Protecting/Radical-Translocating Groups for Carboxylic Acids... 

While often considered undesirable pathways in the past, radical hydrogen transfers have also been shown to constitute intriguing possibilities for organic synthesis. Curran has for instance defined the concept of protection and radical translocation (PRT) groups, fii this context, 2-0-(2-bromo-aryl)dimethylsilyl ethers, aryl amides and 2-bromo-4-methoxyphenyl ethers... 

Curran and co-workers have explored the use of silicon tethers to carry out these reactions. They have successfully demonstrated the 1,5 and 1,6 translocation of a radical that goes on to do intramolecular cyclization reactions. This method was used to synthesize natural product such as crinipellin A22 and 2-(o)-(2-bromoaryl)dimethylsilyl-a-methyl-D-mannopyranoside.24 One of the nice benefits to the use of silicon tethers is that they serve as a hydroxyl-protecting group before and after the reaction is performed. 

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