Tandem sigmatropic rearrangements and cyclizations of propargylic dialkoxy disulfides
作者:Samuel Braverman、Tatiana Pechenick、Hugo E Gottlieb
DOI:10.1016/s0040-4039(02)02653-9
日期:2003.1
The first successful preparation of propargylic dialkoxy disulfides in high yields is reported. These esters afforded novel 6,7-dithiabicyclo[3.1.1]heptane-2-one 6-oxide derivatives via an unprecedented sequence of three [2,3]- and one [3,3]-sigmatropic shifts followed by an intramolecular [2+2] cycloaddition. The latter are structurally related to the zwiebelanes, recently isolated from freshly cut
A series of N-heterocyclic carbene copper(I) and rare copper(II) complexes (NHCCuCl or NHCCuCl2) were covalently immobilized directly on the surface of magneticnanoparticles (MNPs) for the first time. The physicochemical properties were investigated by a broad range of techniques, including SEM and TEM microscopy, and TG analysis. The supported complexes exhibited excellent activity in the Huisgen
Jones et al., Journal of the Chemical Society, 1956, p. 4765,4766
作者:Jones et al.
DOI:——
日期:——
Buta-1,2,3-trienylidene, acylvinylidene and acylalkynyl ruthenium complexes via activation of alkynes with RuCl2(dppe)2. X-ray structure of trans-[Ru(CCHCOCH2Ph)(Cl)(dppe)2]O3SCF3
The activation of several functional alkynes HC=C-C=C-Ph (a), HC=CCOCHPh2 (b) and HC=C-CHOH-CHPh2 (c) with the precursor [RuCl(dppe)(2)]PF6[RuCl(dppe)(2) = Ru}], in situ generated from RuCl2(dppe)(2)NaPF6, has been performed. It selectively produces the buta-1,2,3-trienylidene Ru}=C=C=C=CHR]+PF6- intermediates (I) from a, and acylvinylidene complexes (Ru)=C=CH-COR]+PF6- [R = CH2Ph (3) and R = CHPh2 (5)] from a and b and Ru}=C=CH-CH=CPh2]+PF6- (10) from c. The deprotonation of 3, 5 and 10, respectively, affords acylalkynyl derivatives Ru}-C=C-CO-R] 4, 6 and Ru}-C=C-CH=CPh2] 11. The X-ray diffraction study of trans-[(Cl)(dppe)(2)Ru=C=CHCOCH2Ph]O3SCF3 3, obtained by reaction of Ru}-C=C-C=CPh] with CF3SO3H and water, has been carried out. Crystal data are: a 13.362(4), b 23.669(4), c 42.218(6) Angstrom, orthorhombic space group Pbca, Z=8. The structure shows Ru-C(1) (1.77(1) Angstrom) and C(1)-C(2) (1.36(2) Angstrom) bond distances. (C) 1998 Elsevier Science S.A. All rights reserved.
The First Structurally Characterized Metal Complex with the Molecular Unit M=C=C=C=CR2