Inhibition of Stannane-Mediated Radical Rearrangements by a Recoverable, Minimally Fluorous Selenol
作者:David Crich、Xiaolin Hao、Mathew A. Lucas
DOI:10.1021/ol990590+
日期:1999.7.1
[GRAPHICS]The preparation of a minimally fluorous diaryl diselenide is described. It is demonstrated that this diselenide, reduced in situ to the corresponding selenol, may be used in conjunction with stannanes to prevent a number of radical rearrangements. A 1 M solution of this selenol used in admixture with Breslow's water-soluble stannane can be used to significantly inhibit a cyclopropylcarbinyl ring opening. The combination of the fluorous selenol and the polar stannane permits recovery of the selenol by continuous fluorous extraction and isolation of a stannane-free hydrocarbon product.
Conjugate addition to diethyl azodicarboxylate under organic-perfluorinated biphasic homogeneous catalysis by nickel(II) species
The nickel(II) complex of the Schiff base of salicylaldehyde and 4-perfluorodecylaniline catalyzes the conjugate addition of beta-diketones to electron-deficient substrates. Electrophilic amination with azodicarboxylate affords quaternary centers. The catalyst is recovered in solution and reutilized. Isolation of reaction products is very simple and does not require chromatography. (C) 2000 Elsevier Science Ltd. All rights reserved.