24202-81-1Relevant academic research and scientific papers
Synthesis of Bridged Azacycles and Propellanes via Nitrene/Alkyne Cascades
May, Jeremy A.,Wang, Qinxuan
supporting information, p. 3039 - 3044 (2020/04/20)
A nitrene/alkyne cascade reaction terminating in C-H bond insertion to form functionalized bridged azacycles from carbonazidates is presented. Due to an initial Huisgen cyclization, all carbonazidates reacted with the alkyne in an exo mode in contrast to the use of sulfamate esters, which react predominately in an endo mode. Substrates with different ring sizes as well as different aryl and heteroaryl groups were also explored. Variation of the nitrene tether showed that 7-membered rings were the maximum ring size to be formed by nitrene attack on the alkyne. Examples incorporating stereocenters on the carbonazidate's tether induced diasteroselectivity in the formation of the bridged ring and two new stereocenters. Additionally, propellanes containing aminals, hemiaminals, and thioaminals formed from the bridged azacycles in the same reaction via an acid-promoted rearrangement.
SeO2-Mediated Oxidative Transposition of Pauson-Khand Products
Dibrell, Sara E.,Maser, Michael R.,Reisman, Sarah E.
supporting information, p. 6483 - 6487 (2020/04/30)
Oxidative transpositions of bicyclic cyclopentenones mediated by selenium dioxide (SeO2) are disclosed. Treatment of Pauson-Khand reaction (PKR) products with SeO2 in the presence or absence of water furnishes di- and trioxidized cyclopentenones, respectively. Mechanistic investigations reveal multiple competing oxidation pathways that depend on substrate identity and water concentration. Functionalization of the oxidized products via cross-coupling methods demonstrates their synthetic utility. These transformations allow rapid access to oxidatively transposed cyclopentenones from simple PKR products.
Ethynyl-cyclohexanol: an efficient acetylene surrogate in Sonogashira coupling
Csékei, Márton,Novák, Zoltán,Kotschy, András
, p. 975 - 982 (2008/09/17)
The Sonogashira coupling of aryl halides in the presence of 1-ethynyl-cyclohexanol as an acetylene source provides an efficient method for the synthesis of diarylacetylenes without the isolation of the appropriate arylacetylenes.
Palladium-catalysed alkynylation of 2- or 3-bromopyridine
Zhang, Weiwei,Cheng, Jiang,Huang, Zhengxu,Zhou, Qingqing,Chen, Xunmin,Qian, Jianzhu
, p. 781 - 782 (2007/10/03)
2- or 3-Alkynylpyridines were prepared using a palladium complex, in the absence of copper ions or amines. The mild procedure tolerated a range of 1-alkynes giving 2- or 3-alkynylpyridine in moderate to good yield.
