Sommelet-Hauser rearrangement aminomethylation

The base-induced 2,3-shift in a benzyltrialkylammonium halide (Sommelet-Hauser synthesis) efrects an orr/io-selective aminomethylation of aromatics. A variation (orr/to-selective formylation) is shown in equation (37). Unfortunately, the 1,2-Stevens rearrangement (— 10% 143) of the intervening ylide competes with the 2,3-pathway (— 142). A reliable tool to circumvent this very general difficulty is still unknown. Nonetheless, 2,3-rearrangement pathways can be very efficient as demonstrated by the synthesis of the cyclic amine (144 equation 38). ... 

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