Davies indole synthesis

The Rh-catalyzed annulation of triazoles has been explored by several investigators as a novel indole synthesis. Fokin s team generated azavinyl carbenes with rhodium and parlayed this reaction into an indole synthesis (equation 3) [54], Davies and colleagues described a one-pot indole synthesis from tosyl azide and cyclohexenyl derivatives involving an in situ triazole formation (equation 4) [55], and Lin reported a synthesis of 3-indolylimines using a similar approach (equation 5) [56]. Miura and coworkers effected the Rh-cat-alyzed intramolecular synthesis of 3,4-fused indoles... 

Davies et al. disclosed a one-pot indole synthesis from cyclohexene 154 and tosylazide (155).The reaction proceeds via a click reaction to form the triazole, followed by Rh-based decomposition, pyrrole formation, and oxidation to indole 156. The indoles (and azaindoles) are formed in very good yield and may be substituted with alkyl-, aryl-, or silyl-proteaed alcohols (13JA11712). 

Pyrroles, H.M.L. Davies. Synthesis of Porphyrins with Exocy-clic Rings from Cycloalkenopyrroles, T.D. Lash. Palladium-Catalyzed Coupling Reactions of Indoles, A.R. Martin and Q. Zheng. Cycloaddition Reactions of Indole Derivatives, U. Pindur. Transition-Metal Mediated Synthesis of Carbazole Derivatives, H. J. Knoiker. Synthesis of [b]-Annelated Indoles by Thermal Electrocyclic Reactions, S. Hibino and E. Sugi-no. Total Synthesis of (-) and ent (-) Duocarmycin SA, D.L. Boger. Index. I... 

The first total synthesis of (-)-fumiquinazoline A and B was accomplished by B.B. Snider and co-workers using a Buchwald-Hartwig Pd-catalyzed cyclization of an iodoindole carbamate to construct the imidazoindolone moiety. In order to set up the stereochemistry at the benzylic position of the indole fragment, the double bond was oxidized with the saccharine-derived Davis oxaziridine in the presence of methanol to give the major diastereomer in 65% yield. 

Davies has further exploiled his previously reporied approach to (he tropanc skeleton related to cocaine based on the rhodium catalyzed decomposition of the vinyidiazomethane 81 in the presence of A/-Boc-pyrroIe (82) <01BMCL487>. Reduction of the non-conjugated double bond followed by A -deprotection and N-alkylation provided substrate 83 which was susceptible to conjugate addition of nucleophiles such as 84 in the presence of CuBr to afford 3-p-aryl tropanes which exhibited potent binding affinity for both the dopamine and serotonin transporters. Additionally, this author described the synthesis of various methyl heteroaryldiazoacetate analogues of 81, (me of which possessed an indole function, for use in catalytic asymmetric cyclopropanations . 

Fiirsttier and Mamane described a synthesis of benzol ] indoles using PtCl (Scheme 1, equation 1) [1], andFiirstner and Davies subsequently generalized this indolization (equation 2) [2]. The atmosphere of carbon monoxide accelerates... 

For the carbonylation of 2-nitrostyrenes to indoles, Soderberg and Shriver found an improvement for this transformation and later on applied it in the synthesis of murrayaquinone A [35-37]. By using palladium acetate (6 mol %) together with triphenylphosphine (24 mol %) as the catalytic system, under 4 bar of carbon monoxide in acetonitrile at 70 °C, indoles were produced in moderate to good yields. Davies s group further improved the methodology [38, 39]. With 0.1 mol % palladium (11) trifluoroacetate [Pd(TFA>2] and 0.7 mol % 3,4,7,8-tetramethyl-l,10-phenanthroline (tm-phen) in DMF at 1 bar of CO and 80 °C, indoles were produced in good to excellent yields. 

Contents M.T. Davies-Coleman and D. E. A. Rivett Naturally Occurring 6-substituted 5,6-dihydro-a-pyrones -K. Krohn Building Blocks for the Total Synthesis of Anthracyclinones - M. Lounasmaa and J. Galambos Indole Alkaloid Production in Catharanthus Roseus Cell Suspension Cultures -C. E. James, L. Hough, and R. Khan Sucrose and Its Derivatives. 

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