Intramolecular aromatic 1,5-hydrogen transfer in free radical reactions III. Reactivity of diaryl ketones, ethers, thioethers, sulfoxydes, and sulfones. An experimental and theoretical study.
[reaction: see text] Experiments show that free radical hydrogen shift is significant in the Pschorr cyclization of diphenyl ethers (X = O) and thioethers (X = S) and does not take place with sufoxides (X = SO) and sulfones (X = SO(2)). DFT calculations of the product ratios, activation energies, rate constants for H-transfers, and ring-closings at the UB3PW91/6-31G(d,p) level are in excellent agreement with the experimental results reported here and elsewhere in the literature.
Karady
Sandor
S
Process Research Department, Merck Research Laboratories, Merck and Company, P.O. Box 2000, Rahway, New Jersey 07065, USA. sandor_karady@merck.com
Cummins
Jordan M
JM
Dannenberg
J J
JJ
del Rio
Emma
E
Dormer
Peter G
PG
Marcune
Benjamin F
BF
Reamer
Robert A
RA
Sordo
Tomas L
TL