Nickel-Catalyzed System for the Cross-Coupling of Alkenyl Methyl Ethers with Grignard Reagents under Mild Conditions

Abstract

A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, under mild conditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.

Multicatalytic Stereoselective Synthesis of Highly Substituted Alkenes by Sequential Isomerization/Cross-Coupling Reactions

“…Recent years have witnessed a renewed interest in the use of C–O electrophiles as alternative to aryl halides in metal-catalyzed cross-coupling reactions. , Since the seminal report of Wenkert, , the superiority of Ni catalysts over Pd catalysts has been clearly established. Despite their much reduced reactivity compared to other C–O electrophiles, aryl, benzyl and styrenyl methyl ethers have attracted great attention (Figure -D).…”

Highly E-Selective, Stereoconvergent Nickel-Catalyzed Suzuki–Miyaura Cross-Coupling of Alkenyl Ethers

“…Nickel-catalyzed activations of classically inert bonds have received considerable attention in the last decades . Pioneering studies by Wenkert and others have resulted in the development of practical protocols for the nickel-catalyzed Kumada cross-coupling of various aryl and alkenyl ethers (Scheme a–c) . In all of these cross-coupling protocols, nickel­(II) salts were successfully employed as precatalysts as sacrifical organomagnesium coupling partners led to the in situ formation of the catalytically active species via a transmetalation/reductive elimination.…”

Palladium-Catalyzed Denitrative Mizoroki–Heck Reaction

“…Methyl (E)-4-styrylbenzoate (3Ha) [14] Purification by Isolera ® (hexane/EtOAc = 24:1 to 2:1) afforded 3Ha as a white solid (24.4 mg, 51% yield 8, 141.8, 136.7, 131.2, 130.0, 128.85, 128.75, 128.2, 127.5, 126.8, 126.3, 52 2, 137.1, 137.0, 129.2, 128.7, 128.1, 127.7, 126.8, 126.5, 126.4, 103.5, 65.3; HRMS (DART) m/z calcd for C17H17O2 [M+H] + : 253.1223 found 253.1219. N,N-Dimethyl-3-styrylaniline (3Ja) [16] Purification by PTLC (hexane/EtOAc = 9:1) afforded 3Ja as a pale yellow solid (28.4 mg, 64% yield 8,138.0,137.5,129.6,129.3,128.6,128.2,127.4,126.4,115.0,112.2,110.8,40.7;HRMS (DART) (E)-1-Styrylnaphthalene (3Ka) [7] Purification by GPC afforded 3Ka as a yellow solid (28.5 mg, 62% yield). 1 6, 135.0, 133.7, 131.7, 131.3, 128.7, 128.6, 128.0, 127.8, 126.7, 126.1, 125.81, 125.75, 125.68, 123.7, 123.6; HRMS (DART) m/z calcd for C18H15…”

“…When phenanthroline-type ligands were used (such as L2 and L3), the desired product 3Aa was obtained, albeit in lower yields ( Table 1, entries 13 and 14). Other Buchwald ligands such as XPhos, SPhos, and RuPhos worked, but the yields of 3Aa were lower (Table 1, entries [15][16][17]. t-BuBrettPhos (L4) was effective, but the yield was inferior to BrettPhos ( Table 1, entry 18 vs entry 10).…”