2117-50-2Relevant articles and documents
Synthesis of ethyl 4-chloro-2-oxobut-3-ynoate and its addition to alkyl vinyl ethers
Koldobskii,Solodova,Godovikov,Kalinin
, p. 1568 - 1570 (2009/09/30)
Ethyl 4-chloro-2-oxobut-3-ynoate has been synthesized for the first time and its addition to alkyl vinyl ethers of various structures has been studied.
Novel organoborane Lewis acids via selective boron-tin exchange processes - Steric constraints to electrophilic initiation by the boron halide
Eisch, John J.,Kotowicz, Boguslaw W.
, p. 761 - 769 (2007/10/03)
With the purpose of preparing novel mono- and bidentate organoboron Lewis acids, the scope and limitations of synthesizing the requisite organoboranes by the boron-tin exchange between a boron halide and the appropriate organostannane have been examined in detail. The following organotin derivatives have been obtained either from the corresponding RMgBr or RLi reagent and MenSnCl4-n or from a Barbier procedure using the organic halide, Me3SnCl and magnesium metal: 1,2-bis(trimethylstannyl)ethyne, o-, m-, and p-bis(trimethylstannyl)benzenes, α,o-bis(trimethylstannyl)toluene, α,α-bis(trimethylstannyl)-o-xylene, and 2,2-dimethyl-2-stannaindane. The individual interaction of the 1,2-bis(trimethylstannyl)ethyne and the isomeric bis(trimethylstannyl)benzenes with Et2BBr produced the corresponding bis(diethylboryl)-derivatives. By contrast, with Et2BCl the α,o-bis(trimethylstannyl)toluene gave only o-diethylboryl-α-trimethylstannyltoluene and with BCl3 the α,α′-bis(trimethylstannyl)-o-xylene formed only α,α′-bis-(chlorodimethylstannyl)-o-xylene. Furthermore, in the attempted double boron-tin exchange between o-bis(trimethylstannyl)benzene and BCl3, an unprecedented rearrangement of the 1-(dichloroboryl)-2-(trimethylstannyl)benzene intermediate into its 1-[chloro(methyl)boryl]-2-(chlorodimethylstannyl) isomer was observed. Likewise, o-bis(trimethylstannyl)benzene with PhBCl2 produced by a similar rearrangement 1-[methyl(phenyl)boryl]-2-(chloro-dimethylstannyl)benzene. The thermolysis of such boranes led variously to definite dimers or ill-defined oligomers. Preliminary studies of the properties of these organoboranes have identified the heightened Lewis acidity of 1,2-bis(diethylboryl)ethyne and the π-electron delocalization involving the 2pΖ-boron orbitals in the 9,10-dihydro-9,10-diboraanthracene system. Finally, an electronic mechanism for the boron-tin exchange has been developed to account for the selectivity of the boron halide's attack at unsaturated carbon-tin bonds.
Exchange Reactions between Tri-n-butyl Ethynyl Stannane and Tintetrachloride and Tintetrabromide - Application of 119Sn NMR Spectroscopy
Wrackmeyer, Bernd
, p. 1524 - 1528 (2007/10/02)
The formation of ethynyl stannanes XnSn(CC-H)(4-n) (X = Cl, Br; n = 0-3) via exchange reactions between tri-n-butyl ethynyl stannane and SnX4 is readily monitored by 119Sn NMR spectroscopy.Advantages of 119Sn NMR as compared with 1H or 13C NMR are discussed.The 119Sn and 13C NMR parameters (δ119Sn, δ13C, 1,2J(119Sn13C), 1,2J(13C1H)) for these reaction mixtures are reported.Tri-n-butyl ethynyl stannane and bis(tri-n-butylstannyl)ethyne are both obtained from the reaction of tri-n-butylstannylchloride with Li2C2 in hexane in the presence of excess ethyne. - Key words: Exchange Reactions, Ethynyl Stannanes, 119Sn NMR Spectra, 13C NMR Spectra