Cobalt-Catalyzed Cross-Couplings of Bench-Stable Alkynylzinc Pivalates with (Hetero)Aryl and Alkenyl Halides
作者:Jeffrey M. Hammann、Lucie Thomas、Yi-Hung Chen、Diana Haas、Paul Knochel
DOI:10.1021/acs.orglett.7b01722
日期:2017.7.21
A catalytic system consisting of CoCl2·2LiCl and TMEDA enables the cross-coupling of various electron-poor aryl and heteroaryl halides with various alkynylzinc pivalates. Coupling with alkenyl halides proceeds with retention of configuration.
Sterically Controlled Late-Stage C–H Alkynylation of Arenes
作者:Arup Mondal、Hao Chen、Lea Flämig、Philipp Wedi、Manuel van Gemmeren
DOI:10.1021/jacs.9b10868
日期:2019.11.27
Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials and reagents. These molecules are typically prepared from pre-functionalized starting materials, e.g. using the Sonogashiracoupling, or using directing group-based C-H activation strategies. While highly efficient, these approaches
Sonogashira C,C couplings in a fluorous biphasic system by application of three differently perfluoro-tagged Pd complexes are reported. All three complexes were probed in the coupling of four bromoarenes to three alkynes. The parallel workup procedure allowed for straightforward product isolation and catalyst recovery by simple extraction steps. In particular, the coupling of electron-deficient bromoarenes proceeded with good yields and allowed for the catalyst to be used up to three times.
Rational Syntheses of Porphyrins Bearing up to Four Different Meso Substituents
作者:Polisetti Dharma Rao、Savithri Dhanalekshmi、Benjamin J. Littler、Jonathan S. Lindsey
DOI:10.1021/jo000882k
日期:2000.11.1
using EtMgBr and an acid chloride has been refined. A new procedure for the preparation of unsymmetrical diacyl dipyrromethanes has been developed that involves (1) monoacylation with EtMgBr and a pyridyl benzothioate followed by (2) introduction of the second acyl unit upon reaction with EtMgBr and an acid chloride. The scope of these acylation methods has been examined by preparing multigram quantities
Chemoselective Aerobic Cross-Dehydrogenative Coupling of Terminal Alkynes with Hydrosilanes by a Nanoporous Gold Catalyst
作者:Rahul D. Kavthe、Yoshifumi Ishikawa、Indra Kusuma、Naoki Asao
DOI:10.1002/chem.201803874
日期:2018.10.22
Aerobic cross‐dehydrogenative coupling between terminal alkynes and hydrosilanes occurred in the presence of nanoporous gold catalyst under O2 atmosphere. A variety of alkynylsilanes were synthesized in good‐to‐high yields and the catalyst was easily recovered and reused many times. Furthermore, the chemoselective direct silyl protection of terminalacetylenes of alkynols over the hydroxyl groups was