166757-14-8Relevant academic research and scientific papers
Au(I)-Catalyzed 6-endo-dig Cyclizations of Aromatic 1,5-Enynes to 2-(Naphthalen-2-yl)anilines Leading to Divergent Syntheses of Benzo[α]carbazole, Benzo[c,h]cinnoline and Dibenzo[i]phenanthridine Derivatives
Fu, Jiayue,Li, Bingbing,Wang, Xiugui,Liang, Qida,Peng, Xiaoshi,Yang, Lu,Wan, Tao,Wang, Xinxiu,Lin, Bin,Cheng, Maosheng,Liu, Yongxiang
, p. 46 - 52 (2021/11/20)
A gold(I)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines. The functional group tolerance of this cyclization was examined systematically and a possible mechanism was proposed. The derivatization of 2-(naphthalen-2-yl)aniline was carried out to facile access to benzo[α]carbazole, benzo[c,h]cinnoline and dibenzo[i]phenanthridine derivatives in a divergent way.
Intramolecular C-H activation through gold(I)-catalyzed reaction of iodoalkynes
Morn-Poladura, Pablo,Rubio, Eduardo,Gonzlez, Jos M.
supporting information, p. 3052 - 3055 (2015/04/14)
The cycloisomerization reaction of 1-(iodoethynyl)-2-(1-methoxyalkyl)arenes and related 2-alkyl-substituted derivatives gives the corresponding 3-iodo-1-substituted-1H-indene under the catalytic influence of IPrAuNTf2 [IPr = 1,3-bis(2,6-diisopropyl)phenylimidazol-2-ylidene; NTf2 = bis(trifluoromethanesulfonyl)imidate]. The reaction takes place in 1,2-dichloroethane at 80°C, and the addition of ttbp (2,4,6-tritert-butylpyrimidine) is beneficial to accomplish this new transformation in high yield. The overall reaction implies initial assembly of an intermediate gold vinylidene upon alkyne activation by gold(I) and a 1,2-iodine-shift. Deuterium labeling and crossover experiments, the magnitude of the recorded kinetic primary isotopic effect, and the results obtained from the reaction of selected stereochemical probes strongly provide support for concerted insertion of the benzylic C-H bond into gold vinylidene as the step responsible for the formation of the new carbon-carbon bond.
Platinum and ruthenium chloride-catalyzed cycloisomerization of 1-alkyl-2-ethynylbenzenes: Interception of π-activated alkynes with a benzylic C-H bond
Tobisu, Mamoru,Nakai, Hiromi,Chatani, Naoto
supporting information; experimental part, p. 5471 - 5475 (2009/12/06)
(Chemical Equation Presented) Air-stable and commercially available alkynophilicmetal salts, such as PtCl2, PtCl4, and [RuCl2(CO)3]2, catalyze the cycloisomerization of 1-alkyl-2-ethynylbenzenes to produce substituted indenes even at an ambient temperature. Electrophilically activated alkynes can be intercepted by simple benzylic C-Hbonds at primary, secondary, and tertiary carbon centers. Mechanistic studies, such as labeling studies and kinetic isotope and substituent effects, indicate that the cycloisomerization proceeds through the formation of a vinylidene intermediate and turnover-limiting 1,5-shift of benzylic hydrogen.
Cycloisomerization of aromatic homo and bis-homopropargylic alcohols via catalytic ru vinylidenes: Formation of benzofurans and isochromenes
Varela-Fernandez, Alejandro,Gonzalez-Rodriguez, Carlos,Varela, Jesus A.,Castedo, Luis,Saa, Carlos
supporting information; experimental part, p. 5350 - 5353 (2009/12/30)
Ru-catalyzed cycloisomerizations of aromatic homo- and bis-homopropargylic alcohols effectively afford benzofurans and isochromenes. These processes proved to be chemo- and regioselective (5-, and 6-endo cyclizations) derived from key Ru vinylidene intermediates. The presence of an amine/ammonium base-acid pair is crucial for the catalytic cycle.
An Unusual Example of a 6-Endo-Dig Addition to an Unactivated Carbon-Carbon Triple Bond
Padwa, Albert,Krumpe, Keith E.,Weingarten, M. David
, p. 5595 - 5603 (2007/10/03)
Methyl 2-ethynyl>benzoate was prepared as an intermediate for subsequent conversion to an α-diazo ketone.Under the basic conditions used to hydrolyze the methyl ester, the neighboring hydroxyl functionality underwent reaction with the unactivated acetylenic group, producing a benzopyranyl-substituted α-diazoacetophenone.Treatment of this diazocarbonyl compound with a catalytic quantity of rhodium(II) mandelate afforded a novel dibenzocyclononenone derivative.The reaction proceeds via an initially formed oxonium ylide which rearranges further by means of a 1,2-alkyl shift.A prime factor in determining the direction of internal cyclization to the triple bond is the presence of the carbomethoxy group in the ortho position of the β-phenyl ring.Thus, in contrast with related systems which exhibit a clear preference for 5-exo-dig cyclization at the acetylenic center, the 6-endo-dig addition is the preferred pathway for the o-formyl- and o-carbomethoxy-substituted alkynyl alcohols.Careful monitoring of the reaction actually showed that the reaction proceeds by initial formation of the 5-exo-dig product followed by a novel rearrangement to the 6-endo product.
