Single-Pot Access to Bisorganoborinates: Applications in Zweifel Olefination
摘要:
Zweifel olefination is a catalyst-free reaction that serves alkene functionalization. While most methods employ commercially available boron pinacol esters, we have assembled a sequence in which the two partners of the formal coupling reaction are installed successively, starting from inexpensive boron alkoxides. The in situ formation of bisorganoborinates was accomplished by consecutive reaction of two different organometallic species. This single-pot procedure represents a great advancement in the generation of organoborinates and their involvement in C-C bond formation.
We synthesized twelve hybrids based on curcumin and resveratrol, and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, along with the non-malignant CHO-K1 cell line. Among the tested compounds, hybrids 3e and 3i (for SW480) and 3a, 3e and 3k (for
I<sub>2</sub> catalyzed tandem protocol for synthesis of quinoxalines via sp<sup>3</sup>, sp<sup>2</sup> and sp C–H functionalization
作者:Kamlesh S. Vadagaonkar、Hanuman P. Kalmode、Kaliyappan Murugan、Atul C. Chaskar
DOI:10.1039/c4ra08589b
日期:——
One-pot, atom-economic synthesis of quinoxalines has been achieved through generation of arylglyoxalfrom easily available ethylarenes, ethylenearenes and ethynearenes, and subsequent condensation with o-phenylenediamines. Catalytic I2 with TBHP as an oxidant in DMSO is the system of choice for this dominoreaction involving C–H functionalization/oxidative cyclization. This metal-free, mechanistically
One-Pot Protocol for the Synthesis of Imidazoles and Quinoxalines using<i>N</i>-Bromosuccinimide
作者:Sachin D. Pardeshi、Pratima A. Sathe、Kamlesh S. Vadagaonkar、Atul C. Chaskar
DOI:10.1002/adsc.201700900
日期:2017.12.11
N‐bromosuccinimide (NBS)‐mediated one‐pot, green, efficient and practical synthesis of substituted imidazoles and quinoxalines has been achieved by the reaction of styrenes with N‐arylbenzamidines and o‐phenylenediamines, respectively, in a water:1,4‐dioxane mixture. The reaction involves formation of an α‐bromo ketone as an intermediate in the presence of NBS and water, followed by condensation with
Palladium catalyzed cross-coupling of phenol triflates with organostannanes. A versatile approach for the synthesis of substituted resorcinol dimethyl ethers.
作者:Gabriel Martorell、Angel García-Raso、José M. Saá
DOI:10.1016/0040-4039(90)80227-d
日期:——
-2,6 Dimethoxy-substituted phenol triflates undergo efficient Pd(O) catalyzed cross coupling with organostannanes, thus providing an easy access to substituted resorcinol dimethyl ethers, a common building block of many aromatic polyketides.
The Key Role of the Nonchelating Conformation of the Benzylidene Ligand on the Formation and Initiation of Hoveyda-Grubbs Metathesis Catalysts
作者:Bartosz Bieszczad、Michał Barbasiewicz
DOI:10.1002/chem.201501959
日期:2015.7.13
Experimental studies of Hoveyda–Grubbsmetathesiscatalysts reveal important consequences of substitution at the 6‐position of the chelating benzylideneligand. The structural modification varies conformational preferences of the ligand that affects its exchange due to the interaction of the coordinating site with the ruthenium center. As a consequence, when typical S‐chelated systems are formed as