73540-64-4Relevant academic research and scientific papers
Competition of substituents for ortho direction of metalation of veratric acid
Chau, Nguyet Trang Thanh,Nguyen, Thi Huu,Castanet, Anne-Sophie,Nguyen, Kim Phi Phung,Mortier, Jacques
, p. 10552 - 10557 (2008/12/23)
LTMP (5 equiv) metalates randomly veratric acid (1). Under external quench conditions, the thermodynamically more stable lithium 2-lithio-3,4-dimethoxybenzoate (2) reacts with a variety of electrophiles to give versatile building units that are not easily accessible by conventional means. Under in situ quench conditions (LTMP/TMSCl), a reversal of regioselectivity is observed and 6-trimethylsilyl-3,4-dimethoxybenzoic acid (10) is formed predominantly.
Directed Ortho Metalation of N,N-Diethylbenzamides. Silicon Protection of Ortho Sites and the o-Methyl Group
Mills, Robert J.,Taylor, Nicholas J.,Snieckus, Victor
, p. 4372 - 4385 (2007/10/02)
New general methodology of value in aromatic chemistry based on silicon protection of preferred ortho metalation sites in benzamides and o-methyl groups in o-toluamides (1, 2, Scheme I) is described.According to these methodologies, routes (Scheme II and V) to 1,2,5-, 1,2,4,5-, and 1,2,3-substituted aromatics with a variety of functionalities and oxidation states have been developed (Tables I and II).These tactics are used for the synthesis of difficult to access halo (10a-b, Scheme III) and methyl (21,25, Scheme VI) heterocycles.Ipso bromodesilylation reactions with bromine lead regiospecifically to o-bromobenzamides (12a,c, 14, Scheme IV).Walk-around-the-ring metalation processes provide highly substituted aromatics 27, 28, 29, and 30 (Scheme VII); the X-ray structure of the hexasubstituted derivative 30 shows a significant puckering of the aromatic ring.Cesium fluoride induced carbodesilylation of o-silylbenzamides with benzaldehyde affords, after TsOH cyclization, phthalides (31a-c, Scheme VIII) and constitutes a neutral alternative to the directed ortho metalation approach. α- and α,α-silylated o-toluamides are used in fluoride-mediated carbodesilylation (34a,d, Scheme IX) and desilylative Peterson olefination (35, Scheme X) procedures, respectively.The utility of α-silylated o-toluamide for the synthesis of a tetralin (38, Scheme XI) via an o-quinodimethane species is given.
SILICON IN BENZAMIDE DIRECTED ORTHO METALATION REACTIONS. CARBO- AND BROMO-DESILYLATIONS AND SYNTHESIS OF NATURALLY-OCCURING ANTHRAQUINONES
Mills, R.J.,Snieckus, V.
, p. 483 - 486 (2007/10/02)
Silylated benzamides 2, avaible by directed ortho metalation, undergo fluorideinduced carbodesilylation and ipso bromodesilylation to give usefully-substituted aromatics 3 and 4; these reactions are utilized in a short and efficient synthesis of erythrola
