ruthenium‐catalyzed carbocyclization of 2‐alkynylstyrenes that involves a very rare 1,2‐carbon migration of internal alkynes is reported. Various 1,2‐di ‐and 1,4,7‐trisubstituted naphthalenes are synthesized. Mechanistic studies revealed that this reaction proceeds via a disubstituted vinylidene complex as the key intermediate by 1,2‐carbon migration of the 2‐alkynylstyrenes.
A gold‐catalyzed reaction of phenylene‐tethered allenynes with benzofurans gave 1‐(naphth‐1‐yl)cyclopropa[b]benzofuran derivatives, whereas the reaction of 1‐allenyl‐2‐ethynyl‐3‐methylbenzene derivatives in the absence of benzofurans gave acenaphthenes in good yields. These results can be rationalized by nucleophilic attack of the alkyne moiety on an activated allene to form a vinyl cation intermediate
亚苯基拴链的烯炔与苯并呋喃的金催化反应产生了1-(萘-1-基)环丙烷[ b ]苯并呋喃衍生物,而苯并呋喃不存在时1-烯基-2-乙炔基-3-甲基苯衍生物的反应以高收率得到啶。这些结果可以通过炔基部分在活化的丙二烯上的亲核攻击以形成乙烯基阳离子中间体来合理化。
Enantioselective Folding of Enynes by Gold(I) Catalysts with a Remote <i>C</i><sub>2</sub>-Chiral Element
作者:Giuseppe Zuccarello、Joan G. Mayans、Imma Escofet、Dagmar Scharnagel、Mariia S. Kirillova、Alba H. Pérez-Jimeno、Pilar Calleja、Jordan R. Boothe、Antonio M. Echavarren
DOI:10.1021/jacs.9b06326
日期:2019.7.31
Chiral gold(I) catalysts have been designed based on a modified JohnPhos ligand with a distal C2-2,5-diarylpyrrolidine that creates a tight binding cavity. The C2-chiral element is close to where the C-C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear catalysts have been applied for the enantioselective 5-exo-dig and 6-endo-dig cyclization of different 1,6-enynes
Enantioselective Relay Catalytic Cascade Intramolecular Hydrosiloxylation and Mukaiyama Aldol Reaction
作者:Pu-Sheng Wang、Kang-Nan Li、Xiao-Le Zhou、Xiang Wu、Zhi-Yong Han、Rui Guo、Liu-Zhu Gong
DOI:10.1002/chem.201300702
日期:2013.5.10
Cascading chemistry! The first practical relaycatalyticcascadeintramolecularhydrosiloxylation of arylacetylene and asymmetric Mukaiyamaaldolreaction has been established to give synthetically useful products in high yields and with excellent ee (see scheme).
Visible light-promoted radical cyclization of silicon-tethered alkyl iodide and phenyl alkyne. An efficient approach to synthesize benzosilolines
作者:Xinglong Lin、Zubao Gan、Ji Lu、Zhishan Su、Changwei Hu、Yuebao Zhang、Ya Wu、Lu Gao、Zhenlei Song
DOI:10.1039/c6cc00635c
日期:——
An efficient approach to synthesize benzosiloline has been developed by a visible light-promoted radical cyclization of silicon-tethered alkyl iodide and phenyl alkyne. The nature of the terminal substituent of alkyne...