72755-09-0Relevant articles and documents
O-Methylarenehydroxamates as Ortho-Lithiation Directing Groups. Ti(III)-Mediated Conversion of O-Methyl Hydroxamates to Primary Amides
Fisher, Lawrence E.,Caroon, Joan M.,Jahangir,Stabler, S. Russell,Lundberg, Scott,Muchowski, Joseph M.
, p. 3643 - 3647 (1993)
Reaction of O-methyl benzohydroxamates 2a-c with sec-butyllithium in the presence of TMEDA at -40 deg C regiospecifically generates the highly reactive N,ortho-dilithiated species (e.g. 3).These dilithio species react avidly with a wide spectrum of electrophilic reagents, including alkyl halides, givind adducts which on reduction with TiCl3 are converted into ortho-substituted primary benzamides in excellent yields.Ortho lithiation of O-methyl benzohydroxamates is thus formally equivalent to ortho lithiation of primary benzamides themselves.The utility of these synthetic operations is enhanced by the well-known facility with wich the primary amide moiety can be transformed into other useful functional groups.The conversion of O-methyl hydroxamates to primary amides is shown to be general, as exemplified by transformation of 14a-f to 15a-f.O-Methyl-2-methylbenzohydroxamate (4a) undergoes regiospecific dilithiation on nitrogen and on the methyl group when treated with sec-butyllithium at -70 deg C.These dilithio species react with DMF or "Weinreb-type" amides to give condensation products wich cyclize to N-methoxyisoquinolin-1(2H)-ones under mildly acidic conditions.Removal of the N-methoxy moiety under conditions analogous to those used for O-methyl benzohydroxamate provides N-unsubstituted isoquinolin-1(2H)-ones with high overall efficiency.This process is exemplified by the synthesis of isoquinolin-1(2H)-one 9a, its 3-n-butyl congener 9b, and the tricyclic isoquinolin-1(2H)-ones 20a and 20b from O-methyl 2-methylbenzohydroxamate (4a).
Harnessing hypervalent iodonium ylides as carbene precursors: C-H activation of: N -methoxybenzamides with a Rh(iii)-catalyst
Mayakrishnan, Sivakalai,Tamizmani, Masilamani,Maheswari, Naryanan Uma
supporting information, p. 15462 - 15465 (2020/12/25)
Hypervalent iodonium ylides expeditiously generate carbenes which undergo domino intermolecular C-H activation followed by intramolecular condensation in the presence of N-methoxybenzamide as a starting material and a Rh(iii)-catalyst to afford dihydrophenanthridines. KIE studies and DFT calculations were performed to substantiate the mechanistic pathway. To extend the synthetic utilisation, fluorescent pyranoisocoumarins were achieved by using Rh(iii)-catalyzed peri-C-H/O-H activation/annulation reactions.
Palladium-Catalyzed Inert C?H Bond Activation and Cyclocarbonylation of Isoquinolones with Carbon Dioxide Leading to Isoindolo[2,1-b]isoquinoline-5,7-Diones
Yan, Kelu,Jin, Junbin,Kong, Yong,Li, Bin,Wang, Baiquan
supporting information, p. 3080 - 3085 (2019/05/21)
A palladium-catalyzed inert C?H bond activation and cyclocarbonylation of isoquinolones leading to isoindolo[2,1-b]isoquinoline-5,7-diones under 1 atm of carbon dioxide has been developed. This transformation features high regio- and chemo-selectivity, step-economy, and good functional group tolerance. Most of the corresponding products were obtained in moderate to good yields. It offers an alternative approach for the synthesis of useful diverse isoindolo[2,1-b]isoquinoline-5,7-dione derivatives. (Figure presented.).
Three-Component Synthesis of Isoquinoline Derivatives by a Relay Catalysis with a Single Rhodium(III) Catalyst
Zhou, Chao,Jiang, Jijun,Wang, Jun
supporting information, p. 4971 - 4975 (2019/09/03)
A rhodium(III)-catalyzed one-pot three-component reaction of N-methoxybenzamide, α-diazoester, and alkyne was developed, providing an alternative way to synthesize isoquinoline derivatives. Mechanistically, it is a relay catalysis, and the reaction occurred via successive O-alkylation and C-H activation processes, both of which were promoted by the same catalyst.
Rhodium(III)-catalyzed chemodivergent annulations between: N-methoxybenzamides and sulfoxonium ylides via C-H activation
Xu, Youwei,Zheng, Guangfan,Yang, Xifa,Li, Xingwei
supporting information, p. 670 - 673 (2018/01/28)
Chemodivergent and redox-neutral annulations between N-methoxybenzamides and sulfoxonium ylides have been realized via Rh(iii)-catalyzed C-H activation. The sulfoxonium ylide acts as a carbene precursor, and coupling occurs under acid-controlled condition
Indole- and Pyrrole-BX: Bench-Stable Hypervalent Iodine Reagents for Heterocycle Umpolung
Caramenti, Paola,Nicolai, Stefano,Waser, Jerome
supporting information, p. 14702 - 14706 (2017/09/11)
The one-step synthesis of the bench-stable hypervalent iodine reagents IndoleBX and PyrroleBX using mild Lewis acid catalyzed conditions is reported. The new reagents are stable up to 150 °C and were applied in the C?H arylation of unactivated arenes using either rhodium or ruthenium catalysts. A broad range of heterocyclic systems of high interest for synthetic and medicinal chemistry was accessed in high yields. The developed C?H functionalization could not be achieved using reported reagents or methods, highlighting the unique reactivity of Indole- and Pyrrole-BX.
C-F bond cleavage enabled redox-neutral [4+1] annulation via C-H bond activation
Wang, Cheng-Qiang,Ye, Lu,Feng, Chao,Loh, Teck-Peng
supporting information, p. 1762 - 1765 (2017/02/15)
Using α,α-difluoromethylene alkyne as a nontraditional one-carbon reaction partner, a synthetically novel method for the construction of isoindolin-1-one derivatives via Rh(III)-catalyzed [4+1] annulation reaction is reported. The 2-fold C-F bond cleavage not only enables the generation of desired product under an overall oxidant-free condition but also results in a net migration of carbon-carbon triple bond. In addition, the present reaction protocol exhibits a tolerance of a wide spectrum of functional groups due to the mild reaction conditions employed.
Selective mono-alkylation of N-methoxybenzamides
Chen, Zenghua,Hu, Le'an,Zeng, Fanyun,Zhu, Ranran,Zheng, Shasha,Yu, Qingzhen,Huang, Jianhui
supporting information, p. 4258 - 4261 (2017/04/21)
We report our latest discovery of norbornene derivative modulated highly mono-selective ortho-C-H activation alkylation reactions on arenes bearing simple mono-dentate coordinating groups. The reaction features the use of readily available benzamides and alkyl halides. During the study, we prepared 30 mono-alkylated aryl amides in good yields with good mono-selectivity. We have also demonstrated that structurally rigid alkenes such as norbornene and its derivatives are a good class of ligand and could be used for future direct C-H functionalizations. The utilization of norbornene type ligands for assistance in C-H activation processes has opened a new window for future molecular design using direct C-H functionalization strategies.
Ir(III)-Catalyzed Carbenoid Functionalization of Benzamides: Synthesis of N-Methoxyisoquinolinediones and N-Methoxyisoquinolinones
Phatake, Ravindra S.,Patel, Pitambar,Ramana, Chepuri V.
supporting information, p. 2828 - 2831 (2016/07/06)
A mild and efficient Ir(III)-catalyzed C-H carbenoid functionalization strategy has been developed to access N-methoxyisoquinolinediones and N-methoxyisoquinolinones. The reaction proceeds efficiently in high yield at room temperature over a broad range of substrates without requirement of any additional oxidants or a base.
Regiocontrolled Coupling of Aromatic and Vinylic Amides with α-Allenols to Form γ-Lactams via Rhodium(III)-Catalyzed C-H Activation
Zhou, Zhi,Liu, Guixia,Lu, Xiyan
supporting information, p. 5668 - 5671 (2016/11/17)
A mild, regiocontrolled coupling of aromatic and vinylic amides with α-allenols to form γ-lactams via rhodium(III)-catalyzed C-H activation has been demonstrated. This [4 + 1] annulation reaction provides an efficient method for the synthesis of isoindolinones and 1,5-dihydro-pyrrol-2-ones bearing a tetrasubstituted carbon atom α to the nitrogen atom with good functional group tolerance. The hydroxyl group in the allene substrate is essential in controlling the chemo- and regioselectivity of the reaction probably by coordination interaction with the rhodium catalyst.