Traceless Solid Phase Synthesis with Polystyrene-Bound Tellurium and in Comparison with Polystyrene-Bound Selenium
作者:Thomas Ruhland、Jakob Torang、Henrik Pedersen、Jens Christian Madsen、Kia Svane Bang
DOI:10.1055/s-2004-831202
日期:——
A novel traceless linking strategy by use of polystyrene-bound tellurium is described. The application of the tellurium linker is demonstrated by the solid phase synthesis of a small library of single alkyl aryl ethers containing two points of diversity. Polystyrene-bound tellurium and polystyrene-bound selenium are compared by their cleavage performance under radical conditions (homolysis) at different
ruthenium complex-bound norvaline Boc-L-[Ru]Nva-OMe 1, in which the ONO-pincer ruthenium complex Ru(pydc)(terpy) 2 is tethered to the α-side chain of norvaline, has been demonstrated for the oxidation of methoxybenzenes to p-benzoquinones with a wide scope of substrates and unique chemoselectivity.
Switching on elusive organometallic mechanisms with photoredox catalysis
作者:Jack A. Terrett、James D. Cuthbertson、Valerie W. Shurtleff、David W. C. MacMillan
DOI:10.1038/nature14875
日期:2015.8
step) to occur via a Ni(iii) alkoxide intermediate. Here we demonstrate that visible-light-excited photoredox catalysts can modulate the preferred oxidation states of nickel alkoxides in an operative catalytic cycle, thereby providing transient access to Ni(iii) species that readily participate in reductive elimination. Using this synergistic merger of photoredox and nickel catalysis, we have developed
An Improved Cu-Based Catalyst System for the Reactions of Alcohols with Aryl Halides
作者:Ryan A. Altman、Alexandr Shafir、Alice Choi、Phillip A. Lichtor、Stephen L. Buchwald
DOI:10.1021/jo702024p
日期:2008.1.1
The use of 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4Phen) as a ligand improves the Cu-catalyzed cross-coupling reactions of aryl iodides and bromides with primary and secondary aliphatic, benzylic, allylic, and propargylic alcohols. Most importantly, by employing this catalyst system, the need to use an excessive quantity of the alcohol coupling partner is alleviated. The relatively mild conditions
使用 3,4,7,8-四甲基-1,10-菲咯啉 (Me 4 Phen) 作为配体改善了 Cu 催化的芳基碘化物和溴化物与伯、仲脂肪族、苄基、烯丙基、和炔丙醇。最重要的是,通过使用这种催化剂体系,可以减轻使用过量醇偶联剂的需要。相对温和的条件、较短的反应时间和适度低的催化剂负载量允许在亲电子和亲核偶联伙伴上容忍多种官能团。
Catalytic Cleavage and Reformation of Ethereal σ-Bonds
作者:Masahito Murai、Kazuki Origuchi、Kazuhiko Takai
DOI:10.1246/cl.180361
日期:2018.7.5
Ether-exchange reaction of alkyl aryl ethers with alcohols and thiols via the cleavage of the C(sp2)–O bond is described. Bi(OTf)3 was found to be a most effective catalyst, and etherification of fused-aromatic ethers proceeded efficiently. Monitoring of reactions revealed conceptually new transetherification between two different ethers, which can be regarded as single-bond metathesis under the same