Regioselective Functionalization. 6. Migratory Preferences in Hydroxylamine-<i>O</i>-sulfonic Acid and Schmidt Rearrangements of 7-Substituted Norcamphors

Hydroxylamine-O-sulfonic acid reacted with syn-7-X- and anti-7-Y-substituted norcamphor derivatives [X = H, OMe, Cl, Br, OTos; Y = H, COOMe, Cl, Br, Tos, COOMe(5-exo-Br)], to give solely bridgehead migrated 2-azalactams, except for minor amounts of methylene migrated 3-azalactams from norcamphor (1) and the syn-7-Br ketone 19. Schmidt reactions of the same ketones provided varying mixtures of methylene and bridgehead migrated lactams, except for norcamphor (1) and anti-7-Br ketone 31, which provided solely 3-azalactams. Significant ratios (>0.4) of bridgehead migration to cleavage products were observed in the Schmidt reactions only with 7-OTos ketones 22 and 24 with exo-5-bromo-anti-7-methoxycarbonyl ketone 37. The Schmidt rearrangements most likely involve iminodiazonium ion intermediates in light of the large amounts of cleavage observed relative to lactam formation and the insensitivity of methylene migration to the substituent size in the reactions of syn-7-substituted norcamphors