2-, 3- and 4-Pivaloylamino derivatives of dibenzofuran [compounds (5), (4) and (6), respectively] and analogous 3-, 2- and 1-substituted derivatives of 9-methylcarbazole [compounds (8), (7) and (9), respectively] were subjected to lithiation at 0 degreesC and subsequent reaction with dimethylformamide. Aldehyde formation took place at positions alpha to delta to the heteroatom as follows: alpha for (4) and (7); delta for (5); delta and beta (3 : 1) for (8); and alpha' for (6). No formylation occurred with (9).
2-, 3- and 4-Pivaloylamino derivatives of dibenzofuran [compounds (5), (4) and (6), respectively] and analogous 3-, 2- and 1-substituted derivatives of 9-methylcarbazole [compounds (8), (7) and (9), respectively] were subjected to lithiation at 0 degreesC and subsequent reaction with dimethylformamide. Aldehyde formation took place at positions alpha to delta to the heteroatom as follows: alpha for (4) and (7); delta for (5); delta and beta (3 : 1) for (8); and alpha' for (6). No formylation occurred with (9).