Three Lewis acid catalysed reactions used in a synthesis of the tricyclic core of the marine anti-inflammatory pseudopterosins are reported; the reductive cleavage of an oxirane with inversion, the cyclisation of an α-hydroxy ketenedithioacetal to an arene, and a stereoselective annulation using an allylic sulfone as the electrophile.
Coupling between radical and anion in the outersphere oxidation of α-sulfonyl carbanions. Its role on the product distribution between dimeric olefin and disulfone
作者:Christian Amatore、Touriya El Moustafid、Christian Rolando、André Thiébault、Jean-Noël Verpeaux
DOI:10.1016/s0040-4020(01)87067-8
日期:1991.1
The electrochemical oxidation of α-sulfonylcarbanions is shown to involve a coupling reaction between the electrogenerated radical and the parent anionic species, both on preparative and kinetic grounds. Two routes compete for the further evolution of the ensuing anion radical: (i) a two step desulfonylation leading to the dimeric olefin, the product of an overall catalytic process, (ii) or further
Synthesis, structure, and stability of cyclopentadienyl-(triphenylphosphine)(α-benzenesulfonylalkyl)nickel complexes
作者:M. Julia、H. Lauron、J.N. Verpeaux、Y. Jeannin、C. Bois
DOI:10.1016/0022-328x(88)87107-9
日期:1988.12
moderate yields by reaction of α-sulfonylcarbanions with Cp(PPh3)NiCl; the crystal structure of two of these complexes shows that the nicle atom is linked to the α-carbon of the sulfonyl group and there is no interactioin between the metal and the SO2 moiety. When their solution in benzene are warmed to 90°C, these complexes very cleanly yield the corresponding α,β-unsaturated sulfone (E isomer). An efficient
α-sulfonyl litiated anions are oxidized by cupric carboxylates into β, β-unsaturated sulfones. Primary sulfones lead to pure trans-vinylic sulfones.
α-磺酰基锂阴离子被羧酸铜氧化为β,β-不饱和砜。伯砜生成纯的反式乙烯砜。
Unexpected single electron transfer catalysed cyclisation of prenyl sulphone dimer. Evidence for radical anion coupling in the outer-sphere oxidation of prenyl sulphone carbanion
of metallated phenyl prenyl sulphone leads to a previously unknown cyclic dimer, the formation of which has been rationalized, providing strong evidence for a radical-anion coupling mechanism in outer-sphere oxidative dimerization of α-sulphonyl carbanions.