Larock synthesis

The Larock synthesis was used by Chen and co-workers to synthesize the 5-(triazolylmethyl)tryptamine MK-0462, a potent 5-HTid receptor agonist, as well as a metabolite [391, 392]. Larock employed his methodology to prepare tetrahydroindoles [393],... 

The Larock synthesis was used by Chen and co-workers to synthesize the 5-(triazolyl-methyl)tryptamme MK-0462, a potent 5-HTjn receptor agonist, as well as a metabohte [366], Larock employed his methodology to prepare tetrahydroindoles [367], and Maassarani used this method for the synthesis of /V-(2-pyridyl)indoles [368]. The latter study features the isolation of cyclopalladated Y-phenyl-2-pyridylammes. Rosso and coworkers have employed this method for the industrial-scale synthesis of an antimigraine drug candidate 331. In this paper removal of spent palladium was best effected by trimer-captotriazine (332) although many techniques were explored [369]. 

The Larock synthesis was used to synthesize Merck s rizatriptan (Maxalt, 5-(triazolylmethyl)tryptamine, MK-0462), a potent 5-HTid receptor agonist for the treatment of migraine. " The reaction was carried out on a 25 kg scale. 

Internal Alkynes. Several applications of the Larock synthesis of indoles have been published where heterocycles are used as substrate. f " In the Larock method for indol construction, Pd-catalyzed heteroannulation of internal alkynes using ort/to-iodoanilines are used. Similarly, Pd-catalyzed heteroannulation of internal alkynes using ortho-amino-iodopyridine substrates produces azaindoles (Scheme 103). The method provides a convenient access to a structurally diverse range of 5-, 6-, and 7-azaindoles, 304, 305, and... 

F. Li and R. C. Larock, Synthesis, stmcture and properties of new tung oil-styrene-divinylbenzene copolymers prepared by thermal polymerization . Biomacromolecules, 2003,4,1018-25. 

Heterogeneous palladium catalysts have been prepared by covalent immobilization of palladium (11) complexes onto SBA-15 sdica. The heteroannu-lation of 2-iodoaniline with triethyl(phenylethynyl)silane using these preformed palladium complexes gives excellent yields in Larock synthesis of indoles. These palladium catalysts have been demonstrated to be recyclable through multiple recycling experiments (2010MI179). 

Ladenburg reaction, of pyridine 367 Larock synthesis (isoquinoline) 416 Lautens synthesis (indole) 141... 

D.C. Rogness, N.A. Markina, J.P. Waldo, R.C. Larock, Synthesis of pyrido[l,2-a]indole malonates and amines through aryne armulatiotts,... 

Z. Liu, R.C. Larock, Synthesis of carbazoles and dibenzofurans via cross-coupling of o-iodoanflines and o-iodophenols with silylaryl triflates, Org. Lett. 6 (2004) 3739-3741. 

C. Lu, A.V. Dubrovskiy, R.C. Larock, Synthesis of 9-substituted xanthenes by the condeiwation of ar)mes with orffto-hydroxychalcones. Tetrahedron Lett 53 (2012) 2202-2205. 

Ring Closure Reactions Palladium(II) complexes (PdCl2L2, L=P, CN), covalently immobilized onto SBA-15 silica by a postsynthetic method, were used as catalysts in the Larock synthesis of indoles [86]. The reaction consisted of the heteroannulation of 2-iodoaniline and 2-bromoaniline with triethyl(phenylethynyl)silane showing high activities and selectivities to 3-phenyl-lH-indole 26 (Scheme 17). 

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