Diverse copper(<scp>iii</scp>) trifluoromethyl complexes with mono-, bi- and tridentate ligands and their versatile reactivity
作者:Song-Lin Zhang、Chang Xiao、Hai-Xing Wan
DOI:10.1039/c8dt00291f
日期:——
recombine with the CF3 radical. In contrast, 10, with octahedral geometry, is more rigid. Reactivity studies show that except for ion-pair complex 8, they are highly reactive for the trifluoromethylation of arylboronic acids and the C–H bond of terminal alkynes. Furthermore, syn-fluoro- and -oxy-trifluoromethylation across the triple bond of alkynes can be achieved using 6 and CsF or NaOPh. These results
铜(III)三氟甲基络合物被提议为许多铜促进的三氟甲基化反应的必要中间体,但仍然难以捉摸且很少被探索。我们在此报告了具有不同配位配体(单齿,双齿或三齿)和形式电荷(中性或单阴离子)的各种Cu III –CF 3配合物(6–10)的分离,光谱和X射线晶体学表征L(L是吡啶,2,4,6-三甲基吡啶,喹啉-8-环氧乙烷或2,6-双(2'-吡啶基)吡啶)。正方平面络合物6,7和9,由于弱的Cu-CF显示在溶液中的快速动态行为可能3可以迅速离解并与CF 3自由基复合的键。相反,具有八面体几何形状的10更具刚性。反应性研究表明,除离子对络合物8外,它们对芳基硼酸的三氟甲基化和末端炔烃的C–H键具有高反应性。此外,使用6和CsF或NaOPh可以实现跨越炔烃三键的顺-氟-和-氧基-三氟甲基化。这些结果大大扩展了分离和表征良好的Cu(III)–CF 3的范围 络合物,并建立其广泛的反应性,可能广泛参与铜介导
Cu-Promoted Oxidative Trifluoromethylation of Terminal Alkynes with Difluoromethylene Phosphobetaine
Difluoromethylenephosphobetaine (Ph3P+CF2CO2−, PDFA), a known difluorocarbene reagent, was found to be able to efficiently trifluoromethylate terminalalkynes in the presence of Cu(I) and potassium fluoride. The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.
二氟亚甲基磷酸酯(PH 3 P + CF 2 CO 2 -,PDFA),一种已知的二氟卡宾的试剂,被认为是能够在铜(I)和氟化钾的存在下有效地trifluoromethylate末端炔。转化顺利进行,以中等收率得到相应的三氟甲基化乙炔。
Facile Synthesis of Trifluoromethyl-substituted Enynes: Remarkable Reactivity and Stereoselectivity of Tributyl(3,3,3-trifluoropropynyl)stannane in Carbostannylation of Alkynes
Carbostannylation of alkynes with tributyl(3,3,3-trifluoropropynyl)stannane is found to proceed at room temperature in a syn-manner, giving rise to the corresponding CF3-substituted enynes as a single stereoisomer in good yields. Both terminal and, CF3- or RO2C-substituted internal alkynes are applicable to the addition reaction. Synthetic applications of the adduct are also demonstrated.
Remarkable access to fluoroalkylated trisubstituted alkenes via highly stereoselective cobalt-catalyzed hydrosilylation reaction of fluoroalkylated alkynes
Hydrosilylation reaction of various fluoroalkylated alkynes with Et3SiH in the presence of a catalytic amount of Co2(CO)8 was investigated. The hydrosilylation of the alkynes having fluoroalkyl and aryl groups took place smoothly with good regioselectivity (ca. 80:20). In sharp contrast, the reaction of the alkynes having a fluoroalkyl group and a benzyl-type substituent, or various propargyl alcohols gave the corresponding vinylsilanes in an excellent regio- and stereoselective manner. Treatment of the vinylsilanes with various aldehydes in the presence of Zn(OTf)2 and TBAF afforded the coupling products in good yields.
Selective synthesis of α-trifluoromethyl-β-aryl enamines or vinylogous guanidinium salts by treatment of β-halo-β-trifluoromethylstyrenes with secondary amines under different conditions
作者:Vasiliy M. Muzalevskiy、Valentine G. Nenajdenko、Alexander Yu. Rulev、Igor A. Ushakov、Galina V. Romanenko、Aleksey V. Shastin、Elizabeth S. Balenkova、Günter Haufe
DOI:10.1016/j.tet.2009.06.048
日期:2009.8
β-halo-β-trifluoromethylstyrenes with secondaryamines under different conditions were discovered. Depending on the electronic properties of the starting styrenes and the reaction parameters, two pathways were found. With neat secondaryamines a series of α-trifluoromethyl-β-aryl enamines were prepared in high yields. In contrast, the reactions of the mentioned styrenes with the same amines in polar solvents by substitution