Iron-Catalyzed Regiodivergent Hydrostannation of Alkynes: Intermediacy of Fe(IV)–H versus Fe(II)–Vinylidene
作者:Jianguo Liu、Heng Song、Tianlin Wang、Jiong Jia、Qing-Xiao Tong、Chen-Ho Tung、Wenguang Wang
DOI:10.1021/jacs.0c11448
日期:2021.1.13
iron-aryloxide catalyst (2, X = O-, R = Cy) affords an iron(II) vinylidene intermediate, allowing for gem-addition of the Sn-H to the terminal-carbon producing β-vinylstannanes. These catalytic reactions exhibit excellent regioselectivity and broad functional group compatibility and enable the large-scale synthesis of diverse vinylstannanes. Many new reactions have been established based on such a synthetic
我们报告了一种铁系统 Cp*Fe(1,2-R2PC6H4X),它通过调节离子金属-杂原子键 (Fe-X) 的反应性来控制炔烃的马尔科夫尼科夫和反马尔科夫尼科夫氢氢化。将 nBu3SnH 依次添加到铁-酰胺基催化剂 (1, X = HN-, R = Ph) 中提供了二锡基 Fe(IV)-H 物种,负责跨 C≡C 键的 Sn-H 键的顺式加成生产支链α-乙烯基锡烷。通过芳基氧化铁催化剂 (2, X = O-, R = Cy) 活化炔烃的 C(sp)-H 键,得到亚乙烯基铁 (II) 中间体,允许 Sn-H 与产生β-乙烯基锡烷的末端碳。这些催化反应表现出优异的区域选择性和广泛的官能团兼容性,能够大规模合成多种乙烯基锡烷。
<i>Z</i>-Selective Hydrostannylation of Terminal and Internal C–C Triple Bonds Initiated by the Trityl Cation
作者:Francis Forster、Victoria M. Rendón López、Martin Oestreich
DOI:10.1021/acs.organomet.8b00409
日期:2018.8.27
of n-Bu3SnH across terminal and internal alkynes, including related α,β-unsaturated carboxyl compounds, is reported. The reaction is initiated by the trityl salt [Ph3C]+[B(C6F5)4]− and proceeds through β-tin-stabilized vinyl cations. Their reduction by hydride transfer from n-Bu3SnH explains the high Z-selectivity in the formation of the vinyl stannanes.
The preparation of imides via the palladium-catalyzed coupling reaction of organostannanes is described. The palladium-catalyzed coupling reaction of aryl-, heteroaryl-, and alkenyl(tributyl)stannanes with methyl N-[methoxy(methylthio)methylene]carbamate in the presence of Cu(I) thiophene-2-carboxylate (CuTC) affords imino ethers, which are converted to the corresponding imides in high yield through acid hydrolysis.
Hydrostannylation-Cross-Coupling Strategy for the Stereoselective Synthesis of Alkylidenemalonates and Related α,β-Unsaturated Esters
A method for the stereoselectivesynthesis of alkylidenemalonates and related α,β-unsaturated esters by a hydrostannylation–cross-coupling process has been developed. Pd-catalyzed and radical hydrostannylation of propiolate derivativesstereoselectively provided α-alkoxycarbonyl (E)- and (Z)-vinylstannanes, respectively, which were then converted into alkylidenemalonates by the Stille coupling reaction