The reduction of diarylcarbinols with sodium borohydride/trifluoroacetic acid (TFA),a reaction developed by Gribble and co-workers in 1977,is a convenient method for the preparation of the corresponding diarylmethanes.In 1991,Nutaitis and co-workers demonstrated that this method was also applicable to the reduction of secondary heterocyclic carbinols substituted with any combination of thiophene,furan,benzothiophene,benzofuran,and phenyl ring systems;the presence of 1,3-azole,1,3-benzazole,or pyridyl substituents prevented the reduction,leading to recovered starting material.
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