Cationic oligomerization of bicyclic oxalactam

Abstract

SynopsisCationic oligomerization of bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.l]octan-7-one [abbreviated as BOL (111, was carried out at 04WC with trifluoromethanesulfonic acid and borontrifluoride etherate as catalysts to obtain the oligomer mixture at high yield. From the structural analysis of the isolated dimer, a N-(2(ekarbamoyltetrahydropyran-6(e )-yl)-8-oxa-6azabicyclo[3.2.l]octan-7-one, the oligomerization proceeded through the G 6 N scission in (1) but not through the 6N-7C (amide group) scission as generally observed in common lactams. This peculiar oligomerization must result from the protonation to the oxamide unit (--O--CH--NH4=0) in the BOL molecule. I I

Synthesis and ring-opening polymerization of novel bicyclic oxalactams. 2-Oxa-6-azabicyclo[2.2.2]octan-5-one

“…The cationic polymerization behavior of 2,6-BOL described above significantly differs from that of 8,6-BOL: The latter monomer gave a mixture of dimers and higher oligomers in the presence of cationic initiators such as trifluoromethanesulfonic acid and boron trifluoride etherate. 30 From the spectroscopic analysis of the isolated dimers from racemic and optically active 8,6-BOL, it was concluded that the cationic oligomerization involved the protonation onto the amide nitrogen of 8,6-BOL and the subsequent selective scission of the C(5)-N(6) bond, while the C(5)-0(8) bond was intact.…”