On the role of samarium/HMPA in the post electron-transfer steps in SmI2 reductions.
The reaction of p,p'-dichlorobenzophenone with SmI2 was studied in the presence of variable amounts of HMPA. The electron-transfer step takes place instantaneously. In the presence of excess substrate, the addition of HMPA retarded the rate of coupling to pinacol by a factor of 250. In the presence of an excess of SmI2, the initial rate retardation is followed by a dramatic increase in rate.
Farran
Hani
H
Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.
Hoz
Shmaryahu
S