The ferrocene halogen “dance” has been deemed hardly controllable. Here, we describe the first efficient examples of this reaction. Conversion of 1-fluoro-2-iodo (or 1-chloro-2-iodo) to 1-fluoro-3-iodo (or 1-chloro-3-iodo) ferrocenes was ensured by suitably protecting the free 5-position.

In situ mixtures of CdCl(2)TMEDA (0.5 equiv; TMEDA = N,N,N',N'-tetramethylethylenediamine) or InCl(3) (0.33 equiv) with [Li(tmp)] (tmp = 2,2,6,6-tetramethylpiperidino; 1.5 or 1.3 equiv, respectively) were compared with the previously described mixture of ZnCl(2)TMEDA (0.5 equiv) and [Li(tmp)] (1.5 equiv) for their ability to deprotonate anisole, benzothiazole, and pyrimidine. [(tmp)(3)CdLi] proved to be the best base when used in tetrahydrofuran at room temperature, as demonstrated by subsequent trapping with iodine. The Cd-Li base then proved suitable for the metalation of a large range of aromatics including benzenes bearing reactive functional groups (CONEt(2), CO(2)Me, CN, COPh) or heavy halogens (Br, I), and heterocycles (from the furan, thiophene, pyrrole, oxazole, thiazole, pyridine, and diazine series). Five-membered heterocycles benefiting from doubly activated positions were similarly dideprotonated at room temperature. The aromatic lithium cadmates thus obtained were involved in palladium-catalyzed cross-coupling reactions or simply quenched with acid chlorides.

International audienceThe metallation of aryl ketones was achieved by using LiTMP in the presence of ZnCl2 center dot TMEDA, as evidenced by subsequent interception with iodine or by a palladium-catalysed cross-coupling reaction. One of the synthesized iodo ketones has been further elaborated to reach derivatives of biological interest

Because N-arylation of isatin only worked with iodoferrocene (and in low yield), we employed Narylation of 2-aminophenones and subsequent oxidative cyclization to access various N-arylated isatins. In the course of this work, we observed that N-arylation using 2-iodofuran, 2-iodobenzofuran and 2iodobenzothiophene did not lead to the expected derivatives, but to (benzo)furo-and (benzo)thieno[2,3b]quinolines. Separate cyclization was also performed under acidic conditions on 2-(arylamino)phenones in order to obtain acridines and related compounds. Most of the synthesized compounds were screened for their antiproliferative activity in A2058 melanoma cells, and against a panel of disease-relevant kinases such as mammalian CDK5/p25, PIM1, CLK1, DYRK1A, GSK3α/β, Haspin and leishmanial CK1. The biological results are reported. 1.

A series of methoxy-and fluoro-pyridines have been deprotometalated in tetrahydrofuran at room temperature by using a mixed lithium-zinc combination obtained from ZnCl 2 •TMEDA (TMEDA =

This communication describes the deproto-metalation of a large range of aromatics including heterocycles using a newly developed lithium-cadmium base; the reaction proceeds at room temperature with an excellent chemoselectivity and efficiency, and proved to be regioselective in most cases.

Benzothiophene, benzofuran, benzothiazole and benzoxazole were deprotometalated using the lithium-zinc combination prepared from ZnCl2·TMEDA (TMEDA=N,N,N',N'-tetramethylethylenediamine, 1equiv) and lithium 2,2,6,6-tetramethylpiperidide (LiTMP, 3equiv). Subsequent interception of the 2-metalated derivatives using iodine as electrophile led to the iodides in 81%, 82%, 67% and 42% yields, respectively. These yields are higher (10% more) than those obtained using ZnCl2·TMEDA (0.5equiv) and LiTMP (1.5equiv), except in the case of benzoxazole (10% less). The crude iodides were involved in the N-arylation of pyrrole, indole, carbazole, pyrazole, indazole, imidazole and benzimidazole in the presence of Cu (0.2equiv) and Cs2CO3 (2equiv), and using acetonitrile as solvent (no other ligand) to provide after 24h reflux the expected N-arylated azoles in yields ranging from 33% to 81%. Using benzotriazole also led to N-arylation products, but in lower 34%, 39%, 36% and 6% yields, respectively. A further study with this azole evidenced the impact of 2,2,6,6-tetramethylpiperidine on the N-arylation yields. Most of the C,N'-linked bis-heterocycles thus synthesized (in particular those containing benzimidazole) induced a high growth inhibition of A2058 melanoma cells after a 72h treatment at 10(-5)M.

The [3 + 2] cycloaddition reaction between carbonyl ylides generated from epoxides and ketones (ethyl pyruvate, ethyl phenylglyoxylate, isatin, N-methylisatin and 5-chloroisatin) to give substituted dioxolanes and spirocyclic dioxolane indolinones was investigated. The effect of microwave irradiation on the outcome of the reaction was studied. The thermal reaction between 2,2-dicyano-3-phenyloxirane and N-methylisatin was theoretically studied using DFT methods. This reaction is a domino process that comprises two steps. The first is the thermal ring opening of the epoxide to yield a carbonyl ylide intermediate, whereas the second step is a polar [3 + 2] cycloaddition to yield the final spiro cycloadducts. The cycloaddition presents a low stereoselectivity and a large regio- and chemoselectivity. Analysis of the electrophilicity values and the Fukui functions of the reagents involved in the cycloaddition step allowed the chemical outcome to be explained.