Palladium-Catalyzed Dehydrative Cross-Coupling of Allylic Alcohols and <i>N</i>-Heterocycles Promoted by a Bicyclic Bridgehead Phosphoramidite Ligand and an Acid Additive
作者:Kyungjun Kang、Jaewook Kim、Ansoo Lee、Woo Youn Kim、Hyunwoo Kim
DOI:10.1021/acs.orglett.6b00001
日期:2016.2.5
A mild and efficient dehydrative cross-coupling reaction between allylic alcohols and N-heterocycles using palladium catalysis is reported. A bicyclic bridgehead phosphoramidite (briphos) ligand together with Pd(dba)2 is a highly efficient catalyst, and an acid additive involved in the rate-determining step promotes the catalytic cycle. The coupling reaction of allylic alcohols with N-heterocycles
Tandem transfer hydrogenation–epoxidation of ketone substrates catalysed by alkene-tethered Ru(<scp>ii</scp>)–NHC complexes
作者:Frederick P. Malan、Eric Singleton、Petrus H. van Rooyen、Marilé Landman
DOI:10.1039/c9nj01220f
日期:——
systematically varying the ligand and/or ligand substituents: η5-C5H4R′ (R′ = H, Me), EPh3 (E = P, As), NHC (Im, BIm), where NHC = Im(R)(R′) (R, R′ = Me, Bn, 4-NO2Bn, C2H4Ph, C4H7). Each of the Ru(II)–NHC complexes features an N-alkenyl tether to attain bidentate NHC ligands. All complexes found application as catalysts in the tandem transfer hydrogenation and epoxidation reactions of carbonyl substrates
一系列9环戊二烯基钌(II)配合物-NHC(1-9)已经通过系统地改变配体和/或配体的取代基来合成:η 5 -C 5 H ^ 4 R'(R'= H,Me)时,弗3(E = P,As),NHC(Im,BIm),其中NHC = Im(R)(R')(R,R'= Me,Bn,4-NO 2 Bn,C 2 H 4 Ph,C 4 H 7)。每个Ru(II)–NHC络合物均具有N-烯基系链以获得双齿NHC配体。发现所有配合物均用作羰基底物的串联转移氢化和环氧化反应的催化剂。结果表明,该配合物的催化活性相似,在18小时后的转化率高达69%,并且对各种电子形式的羰基底物具有不同的醇:环氧化物选择性。在NHC配体上具有含硝基取代基的配合物3是唯一的配合物,在18小时的反应时间后,其相对于环氧化物显示出对醇产物的偏爱。
N, N′-Olefin functionalized Bis-Imidazolium Pd(II) chloride N-Heterocyclic carbene complex builds a supramolecular framework and shows catalytic efficacy for ‘C–C’ coupling reactions
reactivity of Pd(II) complex in syn and anti-configuration. Palladium(II) N-heterocyclic carbene (NHC) complex (3) of the ligand 3,3'-(pphenylenedimethylene) bis1-(2-methylallyl)}imidazolium bromide has been synthesized and characterized by several spectroscopic techniques and finally the solid-state structure of 3 has been determined by single-crystal X-ray diffraction studies. The Pd(II) complex possesses
Phosphabarrelene-modified Rh-catalysts: a new and selective route towards hydroxy-functionalized bicyclic imidazoles via tandem reactions
作者:Patrick S. Bäuerlein、Ismael Arenas Gonzalez、Jarno J. M. Weemers、Martin Lutz、Anthony L. Spek、Dieter Vogt、Christian Müller
DOI:10.1039/b911612e
日期:——
8-Hydroxy-6-methyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine was formed selectively in high yields from N-(beta-methallyl)imidazole by a tandem hydroformylation-cyclization sequence, representing a novel one-pot catalytic synthesis of bicyclic imidazole derivatives.
The present invention provides a 2,3-dihydro-6-nitroimidazo[2,1-b]oxazole compound represented by the following general formula:
wherein R
1
represents a hydrogen atom or C1-C6 alkyl group, n represents an integer of 0 to 6, R
2
represents a group —OR
3
or the like, and R
3
represents a hydrogen atom, C1-C6 alkyl group or the like, or R
1
and —(CH
2
)
n
R
2
may bind to each other together with carbon atoms adjacent thereto through nitrogen atoms so as to form a spiro ring represented by the general formula (H):
wherein R
41
is hydrogen, C1-C6 alkyl group or the like. The present compound has an excellent bactericidal action against
Mycobacterium tuberculosis
, multi-drug-resistant
Mycobacterium tuberculosis
, and atypical acid-fast bacteria.