Silicon migration from oxygen to carbon and decarbonylation in methoxytriphenylsiloxycarbene.
[reaction: see text] Thermolysis of 2-methoxy-2-triphenylsiloxy-5,5-dimethyl-Delta(3)-1,3, 4-oxadiazoline affords methyl triphenylsilylformate and methyl triphenylsilyl ether via methoxytriphenylsiloxycarbene. Kinetics show that the carbene undergoes reversible 1,2-triphenylsilyl migration (Brook rearrangement) as well as irreversible decarbonylation. Computed transition states and activation energies (B3LYP/6-31+G) suggest that the migration of the silyl group from oxygen to carbon occurs through an "in plane" transition state with the carbene lone pair forming a new bond to silicon. Decarbonylation involves a four-membered ring, achieved by nucleophilic attack of the oxygen atom of the methoxy group at silicon.
Pezacki
J P
JP
Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada.
Loncke
P G
PG
Ross
J P
JP
Warkentin
J
J
Gadosy
T A
TA