67100-15-6Relevant academic research and scientific papers
Rh(II)-catalyzed [2,3]-sigmatropic rearrangement of sulfur ylides derived from N-tosylhydrazones and sulfides
Li, Yuye,Huang, Zhongxing,Wu, Xinhu,Xu, Peng-Fei,Jin, Jing,Zhang, Yan,Wang, Jianbo
, p. 5234 - 5240 (2012/08/07)
In this paper, Rh2(OAc)4-catalyzed [2,3]-sigmatropic rearrangement of sulfur ylides derived from N-tosylhydrazones and sulfides is reported. A series of tosylhydrazones derived from aldehydes were successfully used for [2,3]-sigmatropic rearrangement by reaction with either allylic phenyl sulfides or propargyl phenyl sulfides. The reaction conditions were optimized and afforded the products in moderate to good yields. In addition, a novel and convenient approach for the synthesis of cyclobutenones and cyclopropanes has been developed through direct oxidation of the rearrangement products.
Elimination and Addition Reactions. Part 41. Nucleophilic Eliminative Fission of Cyclopropanes: the Coiled Spring Effect of Ring Strain on Nucleofugality and its Evaluation
Hughes, Simon,Griffiths, Gwerydd,Stirling, Charles J. M.
, p. 1253 - 1264 (2007/10/02)
Rates have been measured of sulphonyl-activated eliminative ring fissions of a series of six cyclopropanes in which the leaving group is stabilised by alkoxycarbonyl, cyano, or sulphonyl groups.The measurements allow assignment of ranks (nucleofugalities) to carbon leaving groups in systems in which the connection to the leaving group is strained by incorporation in a cyclopropane ring.The values obtained are compered with those obtained for a unstrained (acyclic) analogues.Rank enhancements of about 9(log) units are obtained; these enhancements suggests that free energies of activation for leaving-group expulsion are reduced by about 53 kJmol-1, or about 46 percent of these excess of enthalpy of the strained ring, notwithstanding the small degree of ring fission in the transition structure.The effect of phenyl substitution at the leaving group suggests that cleavage of the ring is very little advanced in the transition structure, although this is variable with the nature of the leaving-group stabilisation.This is the first direct determination of the effect of strain on nucleofugality.
γ- and δ-epoxy sulfones. Formation of different ring-sized products upon reaction with CH3MgI or LiN2
Decesare, John M.,Corbel, Bernard,Durst, Tony,Blount, John F.
, p. 1415 - 1424 (2007/10/02)
γ-Epoxy sulfones in which the epoxide function is terminal yield cyclopropylmethanol derivatives on reaction with methylithium or lithium diisopropylamide.In contrast, treatment of these epoxides with two equivalents of CH3MgI gives only cis-3-phenylsulfonylcyclobutanols.The cis-relationship between the OH and sulfonyl groups was proven in one instance by an X-ray stucture determination.Inernal γ-epoxy sulfones yield cyclopropylmethanols with all bases studied.All δ-epoxy sulfones studied furnished cis-3-phenylsulfonylcyclopentanols upon reaction with the Grignard reagent.These same epoxides gave either cyclopentanols or noncyclic products upon reaction with LDA; no cyclobutane ring containing products were obtained contrary to the expectations based on Stork's results with the corresponding epoxy nitriles (ref. 2).The mechanism of the Grignard-mediated reaction involves epoxide opening by iodide ion, α-sulfonyl Grignard formation, and, finally, cyclization.When LDA or CH3Li is used the products are formed by an intramolecular SN2 opening of the epoxide by an α-lithio sulfone.
