Mild and Selective Palladium-Catalyzed Dimerization of Terminal Alkynes To Form Symmetrical (<i>Z</i>,<i>Z</i>)-1,4-Dihalo-1,3-dienes
作者:Jin-Heng Li、Yun Liang、Ye-Xiang Xie
DOI:10.1021/jo0486645
日期:2004.11.1
A regioselective and stereoselective palladium-catalyzeddimerization of terminal alkynes method for the synthesis of symmetrical (Z,Z)-1,4-dihalo-1,3-dienes is presented. In the presence of a catalytic amount of PdX2 and 3 equiv of CuX2 (X = Cl and Br), terminal alkynes were dimerized to afford (Z,Z)-1,4-dihalo-1,3-dienes in good yields. The results showed that the effect of solvent had a fundamental
dimerization of terminalalkynes with trichloroacetyl chloride as chlorine donor proceeds in the presence of rhodium catalysts to give (Z,Z)-1,4-dichloro-1,3-butadienes stereoselectively. Ligand screening has revealed that reactions using sterically bulky and electron-donating ligands like trimesitylphosphine are high yielding. The reaction is compatible with a range of functional groups to give the title
The Application of 1,2-Oxazinanes as Chiral Cyclic Weinreb Amide-Type Auxiliaries Leading to a Three-Component, One-Pot Reaction
作者:Gerhard Hilt、Jan Fährmann、Ludmila Hermann
DOI:10.1055/a-1683-0484
日期:2022.4
1,2-Oxazines were synthesised via a copper-catalysed aerobic acylnitrosoDiels–Alderreaction from 1,4-disubstituted 1,3-dienes and N-Boc-hydroxylamine. From this, 1,2-oxazinanes were obtained in a novel follow-up reaction path. The stability of several 1,2-oxazines and 1,2-oxazinanes towards organometallic compounds was tested to rate their operability as cyclic chiral Weinreb amide auxiliaries.