Atom-Efficient Metal-Catalyzed Cross-Coupling Reaction of Indium Organometallics with Organic Electrophiles

Abstract

The novel metal-catalyzed cross-coupling reaction of indium organometallics with organic electrophiles is described. Triorganoindium compounds (R(3)In) containing alkyl, vinyl, aryl, and alkynyl groups are efficiently prepared from the corresponding lithium or magnesium organometallics by reaction with indium trichloride. The cross-coupling reaction of R(3)In with aryl halides and pseudohalides (iodide 2, bromide 5, and triflate 4), vinyl triflates, benzyl bromides, and acid chlorides proceeds under palladium catalysis in excellent yields and with high chemoselectivity. Indium organometallics also react with aryl chlorides as under nickel catalysis. In the cross-coupling reaction the triorganoindium compounds transfer, in a clear example of atom economy, all three of the organic groups attached to the metal, as shown by the necessity of using only 34 mol % of indium. The feasibility of using R(3)In in reactions with different electrophiles, along with the high yields and chemoselectivities obtained, reveals indium organometallics to be useful alternatives to other organometallics in cross-coupling reactions.

A Novel Geranylgeranyl Transferase Inhibitor in Combination with Lovastatin Inhibits Proliferation and Induces Autophagy in STS-26T MPNST Cells

“…Purification by flash chromatography (hexanes/ethyl acetate 95:5) gave 313 mg (59%) of compound 3 as a colorless oil. Note that this procedure using trimethylindium (Perez et al, 2001) affords superior results to the Stille coupling procedure with tetramethyltin used in previous work (Zahn et al, 2001) on 2Z-GGPP (compound 9).…”

“…In a flame-dried, argon-flushed flask were placed triflate compound 2 (750 mg, 1.6 mmol), Pd(PPh 3 ) 2 Cl 2 (11.2 mg, 0.016 mmol), and 15 ml of tetrahydrofuran (THF). The reaction mixture was heated to reflux at 70°C, and (CH 3 ) 3 In (Perez et al, 2001) (15 ml, 1.5 mmol in THF) was added dropwise. After 4 h, 2 ml of MeOH was added, and the reaction mixture was concentrated.…”

The Mechanisms of the Stille Reaction

“…[15] Besides the two prominent members already mentioned, the family of palladium-catalyzed cross-coupling reactions includes the Hiyama, [16][17][18] Sonogashira, [19] Kumada, [20] and Negishi reactions, [21] and related reactions. [22,23] Cross-coupling reactions are also somewhat related to the Heck reaction (the alkenylation of organic electrophiles). [24] However, although the first step in both processes is identical (activation of the organic electrophile by oxidative addition to Pd), there is no transmetalation step in the Heck reaction, in which the CÀC bond is formed through an insertion step, followed by a b-hydride elimination to form the substituted alkene product.…”

Regio‐ und chemoselektive Metallierung von Arenen und Heteroarenen mit gehinderten Metallamidbasen

“…Zugabe von LiN(SiMe 3 ) 2 (À50 8C, 1 h) liefert ein ZinkAmidocuprat, [221] das nach Zusatz von PhI(OAc) 2 in einer oxidativen Aminierung zu dem 5-aminierten Thiazol 354 reagiert (82 % Ausbeute; Schema 60). [222] Ein großer Vorteil von TMP 2 Zn·2 LiCl (5) (25 8C, 8 h), [226,227] [215] Dies ist durch das Fehlen von MgCl 2 zu erklären, das sich in verwandten Reaktionen als leistungsstarke Lewis-Säure erwies. [229] Kürzlich wurde entdeckt, dass die Lewis-Säure BF 3 mit einigen TMP-Basen, wie 2, [230] 5 [230] oder TMP 4 Zr, [231] kompatibel ist.…”