We have found that boron trifluoride-methanol complex (BTMC) is an effective non-depurinating detritylating agent in automated DNA synthesis. Dichloroacetic acid (DCA) is at present widely used for the deprotection of the 5'-hydroxyl group prior to coupling the next nucleotide (1); however, the protected purine bases, 6'-isobutyryl-2'-deoxyguanosine and 4'-benzoyl-2'-deoxyadenosine, are unstabl...
