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.