A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described,which is promot...A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described,which is promoted by a cooperative action of catalytic CuBr2,2,2,6,6-tetramethyl-1-piperidinyloxy(TEMPO)and O2.The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy,which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.展开更多
A novel 22MnMoB hot stamping steel was designed. The continuous cooling transformation （CCT） measurement of the 22MnMoB steel showed that the ferrite-bainite microstructure could be obtained at cooling rates lower t...A novel 22MnMoB hot stamping steel was designed. The continuous cooling transformation （CCT） measurement of the 22MnMoB steel showed that the ferrite-bainite microstructure could be obtained at cooling rates lower than 25 ℃/s, and the complete martensite structure required the cooling rate higher than 30 ℃/s. The experiments with non-uniform die temperatures were carried out to obtain tailored properties. The results showed that strength of 1 411 MPa and elon- gation of 6% could be obtained in the hard zone, and strength of 916 MPa and elongation of 9% could be obtained in the soft zone, which can be realized by controlling the die temperature at 400 ℃. The transition zone was found smooth and could be beneficial to reduce the stress concen tration and therefore improve the performance of components.展开更多
A new,gen era I palladium-catalyzed oxidative strategy for the cleavage of the C=C triple bond is presented.By employing PdCI2/CuBr2/TEMPO and air as the catalytic system and H2O as the carbonyl oxygen atom source,a w...A new,gen era I palladium-catalyzed oxidative strategy for the cleavage of the C=C triple bond is presented.By employing PdCI2/CuBr2/TEMPO and air as the catalytic system and H2O as the carbonyl oxygen atom source,a wide range of 2-alkynyl carbonyl compounds,including 1,3-disubstituted prop-2-yn-l-ones,propiolamides and propiolates,lost an alkynyl carbon to access various 1,2-dicarbonyl compounds,e.g.,1,2-diones,2-keto amides and 2-keto esters,through Wacker oxidation,intramolecular cyclization and C—C bond cleavage cascades.展开更多
基金supported by the National Natural Science Foundation of China(21625203,21871126)the Opening Fund of KLCBTCMR,Ministry of Education(KLCBTCMR18-02)
文摘A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described,which is promoted by a cooperative action of catalytic CuBr2,2,2,6,6-tetramethyl-1-piperidinyloxy(TEMPO)and O2.The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy,which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.
基金financially supported by National Natural Science Foundation of China(Grant No.U1560204)Fundamental Research Funds for the Central Universities(Grant No.N150705001)National Key Research and Development Program of China(Grant No.2016YFB0101605)
文摘A novel 22MnMoB hot stamping steel was designed. The continuous cooling transformation （CCT） measurement of the 22MnMoB steel showed that the ferrite-bainite microstructure could be obtained at cooling rates lower than 25 ℃/s, and the complete martensite structure required the cooling rate higher than 30 ℃/s. The experiments with non-uniform die temperatures were carried out to obtain tailored properties. The results showed that strength of 1 411 MPa and elon- gation of 6% could be obtained in the hard zone, and strength of 916 MPa and elongation of 9% could be obtained in the soft zone, which can be realized by controlling the die temperature at 400 ℃. The transition zone was found smooth and could be beneficial to reduce the stress concen tration and therefore improve the performance of components.
基金the National Natural Scienee Foundation of China(Nos.21625203 and 21871126)the Opening Fund of KLCBTCMR,Ministry of Education(No.KLCBTCMR18-02)for financial support.
文摘A new,gen era I palladium-catalyzed oxidative strategy for the cleavage of the C=C triple bond is presented.By employing PdCI2/CuBr2/TEMPO and air as the catalytic system and H2O as the carbonyl oxygen atom source,a wide range of 2-alkynyl carbonyl compounds,including 1,3-disubstituted prop-2-yn-l-ones,propiolamides and propiolates,lost an alkynyl carbon to access various 1,2-dicarbonyl compounds,e.g.,1,2-diones,2-keto amides and 2-keto esters,through Wacker oxidation,intramolecular cyclization and C—C bond cleavage cascades.
