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961.
Malcolm R. Banks J. I. G. Cadogan Ian Gosney Philip K.G. Hodgson David R. Rodger 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):381-384
Abstract Whereas arylmetaphosphates (ArOPO2) tend to cyclise by intramolecular C-H insertion (phosphorylation) when generated in the gas phase, their alkyl-substituted counterparts exhibit non-electrophilic behaviour and give rise to alkenes by an unusual 1,2-methyl shift induced by a combination of hydrogen abstraction with concomitant elimination of metaphosphoric acid (HOPO2). 相似文献
962.
963.
Ian C. Watson André Schumann Haoyang Yu Prof. Dr. Emma C. Davy Dr. Robert McDonald Dr. Michael J. Ferguson Prof. Dr. Christian Hering-Junghans Prof. Dr. Eric Rivard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(41):9678-9690
New N-heterocyclic olefins (NHOs) are described with functionalization on the ligand heterocyclic backbone and terminal alkylidene positions. Various PdII–NHO complexes have been formed and their use as pre-catalysts in Buchwald–Hartwig aminations was explored. The most active system for catalytic C−N bond formation between hindered arylamine and arylhalide substrates was accessed by combining a backbone methylated NHO with [Pd(cinnamyl)Cl]2 in the presence of NaOtBu as a base. In these active systems evidence suggests that catalysis is mediated by colloidal palladium metal, highlighting a different coordination ability of NHOs in comparison with commonly used N-heterocyclic carbene co-ligands. 相似文献
964.
965.
966.
967.
Peyton W. Roth Ahlam M. Armaly Ian McCraw James H. Tryon Hayden M. Rudd Brian C. Goess 《Tetrahedron letters》2018,59(39):3586-3588
The first total syntheses of the furanosesquiterpenoids hibiscone B and acyl hibiscone B are reported. The chemistry used to prepare hibiscone B solves an important challenge to the synthesis of other members of the furanosesquiterpenoid family of natural products, for which the parent molecule, hibiscone C, has shown promising biological activity. 相似文献
968.
Lee R. Collins Gabriele Hierlmeier Dr. Mary F. Mahon Dr. Ian M. Riddlestone Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3215-3218
The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH3 and P4. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR2], exhibiting barriers to migratory insertion which increase in the order MR2 = ZnEt2 < ZnMe2 < CdMe2. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H). 相似文献
969.
John Tyman Shoreh Ghorbanian M. Muir Vasiliki Tychopoulous Ian Bruce Ian Fisher 《合成通讯》2013,43(1-2):179-188
The nucleophilic displacement reactions of 2- and 4- halogenonaphthalic-1,8, anhydrides and the N-imides, of 4,7- dichloroquinolines, the alkylation of lithio alkynes, the methylation of ethyl or methyl diacetylacetate and a variety of related reactions are greatly facilitated in N-methylpyrrolidinone as aprotic solvent. 相似文献
970.
JPC – Journal of Planar Chromatography – Modern TLC - A simple and rapid method for analysis of four major triterpenoids in Centella asiatica preparations is described. Thin-layer... 相似文献