Iron-mediated sp-sp3 C-C bond formation through the cross dehydrogenative coupling (CDC) of terminal alkynes with benzylic ethers or alkanes has been developed. The inexpensive iron salt is used as the catalyst to make this transformation environmentally benign.
Practical and Highly Selective CH Functionalization of Structurally Diverse Ethers
作者:Miao Wan、Zhilin Meng、Hongxiang Lou、Lei Liu
DOI:10.1002/anie.201407083
日期:2014.12.8
A trityl ion mediated CHfunctionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemoselectivity and good functional group tolerance. The protocol also exhibits excellent regio‐ and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highlyfunctionalized disubstituted 2,5‐trans tetrahydrofurans
Structurally Diverse α-Substituted Benzopyran Synthesis through a Practical Metal-Free C(sp<sup>3</sup>)–H Functionalization
作者:Wenfang Chen、Zhiyu Xie、Hongbo Zheng、Hongxiang Lou、Lei Liu
DOI:10.1021/ol503004a
日期:2014.11.21
A trityl ion-mediated practical C–H functionalization of a variety of benzopyrans with a wide range of nucleophiles (organoboranes and C–H molecules) at ambient temperature has been disclosed. The metal-free reaction has an excellent functional group tolerance and high chemoselectivity and displays a broad scope with respect to both benzopyran and nucleophile partners, efficiently affording a collection
Enantioselective Copper-Catalyzed Alkynylation of Benzopyranyl Oxocarbenium Ions
作者:Harathi D. Srinivas、Prantik Maity、Glenn P. A. Yap、Mary P. Watson
DOI:10.1021/acs.joc.5b00364
日期:2015.4.17
We have developed highly enantioselective, copper-catalyzedalkynylations of benzopyranyl acetals. By using a copper(I) catalyst equipped with a chiral bis(oxazoline) ligand, high yields and enantioselectivities are achieved in the alkynylation of widely available, racemic isochroman and chromene acetals to deliver α-chiral oxygen heterocycles. This method demonstrates that chiral organometallic nucleophiles
Synergistic Gold(I)/Trimethylsilyl Catalysis: Efficient Alkynylation of N,O-Acetals and Related Pro-Electrophiles
作者:Malina Michalska、Olivier Songis、Catherine Taillier、Sean P. Bew、Vincent Dalla
DOI:10.1002/adsc.201400169
日期:2014.6.16
This unprecedented manifold opens avenues for developing synergistic silyl‐gold(I)‐catalyzed alkynylation strategies of diverse pro‐electrophiles which were heretofore unattainable, the proof of concept being principally exemplified herein with the first catalytic alkynylation of N,O‐acetals. The reaction proceeds at low catalyst loading, employs mild reaction conditions, is easily scalable, and affords
我们报告了一种独特的机理指导的反应,该反应增强和扩展了目前容易产生的乙炔化金(I)的化学空间。我们的策略利用了具有特定抗衡离子(LAuX – X =三氟甲磺酸或三氟甲磺酸的金(I)嗜碳催化剂的倾向。 )有效激活和去甲硅烷基化三甲基甲硅烷基炔烃,从而原位介导形成等量和催化量的可调强度的甲硅烷基路易斯酸(TMSX)和亲核性金(I)乙炔化物。这种空前的流形为开发各种原亲电子的协同甲硅烷基金(I)催化的炔基化策略开辟了道路,这是迄今为止无法实现的,本文主要以N,O-乙缩醛的首次催化炔基化为例来证明概念验证。该反应在低催化剂负载下进行,采用温和的反应条件,易于扩展,并以良好或优异的产率提供炔丙基内酰胺产物。此外,它完全适用于各种结构和功能的底物,并且还可以扩展到除N,O-乙缩醛以外的其他亲电子试剂。已经进行了控制实验,这些实验强烈支持了我们的双重反应机理建议,与TMSNTf 2相比)和所使用的金抗衡