Alkynyl Thioethers in Gold-Catalyzed Annulations To Form Oxazoles
作者:Raju Jannapu Reddy、Matthew P. Ball-Jones、Paul W. Davies
DOI:10.1002/anie.201706850
日期:2017.10.16
regioselective, and convergent access to densely functionalized oxazoles is realized in a functional-group tolerant manner using alkynylthioethers. Sulfur-terminated alkynes provide access to reactivity previously requiring strong donor-substituted alkynes such as ynamides. Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes
Highly regioselective synthesis of 2,4,5-(hetero)aryl substituted oxazoles by intermolecular [3+2]-cycloaddition of unsymmetrical internal alkynes
作者:Elli Chatzopoulou、Paul W. Davies
DOI:10.1039/c3cc45410j
日期:——
A robust N-nucleophilic 1,3-N,O-dipole equivalent reacts with unsymmetrical internal alkynes under gold catalysis. Conjugation from a remote nitrogen lone pair enables and controls this convergent and highly regioselective process.
Rh(
<scp>III</scp>
)‐Catalyzed Diverse C—H Functionalization of Iminopyridinium Ylides
作者:Zhenzhen Dong、Pengfei Li、Xingwei Li、Bingxian Liu
DOI:10.1002/cjoc.202100203
日期:2021.9
Divergent synthesis of useful skeletons has been realized via rhodium(III)-catalyzed C—H activation of iminopyridinium ylides and coupling with various unsaturated coupling reagents. Isocoumarins and isoquinolones were obtained via cleavage of the C—N or N—N bond in the ylidic directing group, while fluorinated alkenes were delivered with the directing group intact. The reactions occurred with wide
Reaction of Diphenylcyclopropenethione with Pyridinium Imines
作者:J. W. Lown、K. Matsumoto
DOI:10.1139/v72-090
日期:1972.2.15
Reaction of diphenylcyclopropenethione with a variety of N-substituted pyridinium imines in refluxing benzene gives 2,4,5-trisubstituted-6H-1,3-oxazin-6-thiones in good to excellent yields. The structure of 2,4,5-triphenyl-6H-1,3-oxazin-6-thione prepared in this manner was proven by oxidation and by hydrolysis to the known 2,4,5-triphenyl-6H-1,3-oxazin-6-one. In the preparation of 4,5-diphenyl-2-ethoxy-6H-1
Visible‐Light‐Promoted Radical Cyclization and N−N Bond Cleavage Relay of N‐Aminopyridinium Ylides for Access to 2,3‐Difunctionalized Indoles
作者:Meng‐Meng Xu、Wen‐Bin Cao、Xiao‐Ping Xu、Shun‐Jun Ji
DOI:10.1002/adsc.202200248
日期:2022.7.5
accurate difunctionalization reaction undergoes a tandem process involving a radical-mediated 1,3-dipolar cycloaddtion which generated from the single-electron oxidation of N-aminopyridinium ylides, a cleavage of the N−N bond as well as an oxidation of indoline ring. The electrophilic pyridyl and nucleophilic amino groups can be installed simultaneously into a wide range of indoles under mild and metal-free