Oxidative Intramolecular 1,2‐Amino‐Oxygenation of Alkynes under Au
<sup>I</sup>
/Au
<sup>III</sup>
Catalysis: Discovery of a Pyridinium‐Oxazole Dyad as an Ionic Fluorophore
作者:Aslam C. Shaikh、Dnyanesh S. Ranade、Pattuparambil R. Rajamohanan、Prasad P. Kulkarni、Nitin T. Patil
DOI:10.1002/anie.201609335
日期:2017.1.16
Oxidative intramolecular 1,2‐amino‐oxygenation reactions, combining gold(I)/gold(III) catalysis, is reported. The reaction provides efficient access to a structurally unique ionic pyridinium‐oxazole dyad with tunable emission wavelengths. The application of these fluorophores as potential biomarkers has been investigated.
Tetra(arylalkynyl)pyridines and tetra(arylalkenyl)pyridines and their benzene analogues were prepared by palladium‐catalyzed cross‐coupling reactions from the commercially available chlorinated substrates in good to excellent yields. The photophysicalproperties of selected compounds were investigated and compared to each other. Very good fluorescence quantum yields were observed, especially for the pyridine derivatives
Zn-ProPhenol Catalyzed Enantioselective Mannich Reaction of 2<i>H</i>-Azirines with Alkynyl Ketones
作者:Barry M. Trost、Chuanle Zhu
DOI:10.1021/acs.orglett.0c03737
日期:2020.12.18
The enantioselective Mannich reaction of 2H-azirines with alkynyl ketones is achieved under Zn-ProPhenol catalysis, delivering various aziridines with vicinal tetrasubstituted stereocenters in high yields with excellent enantioselectivities. The bimetallic Zn-ProPhenol complexes activate both the nucleophile and the electrophile in the same chiral pocket. A unique intramolecular hydrogen bond is observed
Synthesis of fluorescent 2,3,5,6-tetraalkynylpyridines by site-selective Sonogashira-reactions of 2,3,5,6-tetrachloropyridines
作者:Peter Ehlers、Andranik Petrosyan、Antje Neubauer、Timo Bröse、Stefan Lochbrunner、Tariel V. Ghochikyan、Ashot S. Saghyan、Peter Langer
DOI:10.1039/c4ob01292e
日期:——
6-tetraalkynylpyridines were prepared by tetra-fold Sonogashirareactions of the corresponding 2,3,5,6-tetrachloropyridines. 2,6-Dialkynyl-3,5-dichloropyridines were prepared by site-selectiveSonogashirareactions from various 4-unsubstituted and 4-substituted tetrachloropyridines. Subsequent two-fold Sonogashirareactions of the products allowed for the synthesis of various 2,3,5,6-tetraalkynylpyridines containing
An iron-based catalytic system was developed for the cross-coupling of 1-bromoalkynes with terminalalkynes to selectively generate unsymmetrical 1,3-butadiynes in water under air. It was found that a combination of 1-bromoalkynes derived from less acidicterminalalkynes with more acidic counterparts would greatly enhance yields and selectivity for unsymmetrical 1,3-butadiynes. The reaction was also