Noncatalytic Organic Synthesis Using Supercritical Water: The Peculiarity Near the Critical Point.
Pinacol and Beckmann rearrangements can be carried out effectively by using supercritical water (scH(2)O) both as an acid catalyst as well as a medium. In the near-critical region not only are the rates significantly accelerated (see picture), but the nature of supercritical water can be adjusted to give weak acidity, which opens a new reaction pathway to a Diels-Alder adduct between dehydrated products.
Ikushima
Y
National Industrial Research Institute of Tohoku, 4-2-1 Nigatake, Miyagino-ku, Sendai 983-8551 (Japan).
Hatakeda
K
Sato
O
Yokoyama
T
Arai
M