Is Fe-catalyzed ortho C–H Arylation of Benzamides Sensitive to Steric Hindrance and Directing Group?

Abstract

The previously reported Fe-catalyzed ortho C− H arylation of benzamides relied on bi-or tridentate amide groups and specific iron ligands and was sensitive to steric hindrance. By using new mixed titanates, our present protocol accommodates various weakly coordinating benzamides and tolerates high steric hindrance and sensitive functional groups only under the catalysis of FeCl 3 and TMEDA. A wide range of privileged condensed ring compounds can thus be facilely accessed.

Nickel-Catalyzed Cross-Electrophile Coupling of 1,2,3-Benzotriazin-4(3H)-ones with Aryl Bromides

“…13 C­{ 1 H} NMR (101 MHz, CDCl 3 ): δ 170.3, 140.1, 139.4, 138.2, 135.5, 130.1, 130.0, 129.2, 128.8, 128.51, 128.45, 127.5, 125.7, 26.6, 21.4 ppm. The spectroscopic data for this product match the literature data …”

“…The spectroscopic data for this product match the literature data. 5 N-Methyl-4′-vinyl-[1,1′-biphenyl]-2-carboxamide (3al). The reaction was performed following the general procedure with NiBr 2 • glyme (3.5 mg, 0.01 mmol), bipy (2.3 mg, 0.015 mmol), 3methylbenzo [d][1,2,3]triazin-4(3H)-one (1a) (16.1 mg, 0.10 mmol), 1-bromo-4-ethenylbenzene (2l) (32.7 μL, 0.2 mmol), and Zn (13.1 mg, 0.2 mmol, 2 equiv).…”

“…The methods for ortho -arylation of benzamide derivatives often rely on the ability of this group to coordinate to metals. As a result, the transition-metal-catalyzed (including Fe, Ni, Pd, Ir, and Ru) directed ortho -arylation of sp 2 C–H bonds has seen extensive development (Scheme a). A less common approach is the nickel-catalyzed denitrogenative ortho -arylation of benzotriazinones (Scheme b).…”

Weak-Coordination in C–H Bond Functionalizations Catalyzed by 3d Metals

“…Recently benzamide derivatives using 2-substituted aryl Grignard reagents (Scheme 46). 126 The use of mixed titanate was crucial in the success of the C−H arylation process. Importantly, TMPMgCl•LiCl (2,2,6,6-tetramethylpiperidinylmagnesium chloride) deprotonates the amide acidic hydrogen with concomitant release of TMPH which does not poison the Grignard reagent.…”

Fe-Catalyzed Difunctionalization of Aryl Titanates Enabled by Fe/Ti Synergism

“…Initially we used the reactions in Scheme as a model to explore the factors affecting the Fe/Ti exchange reaction and the ortho C–H ferration of the C–Ti bond. The aryl titanates ( 1 ), in situ generated by mixing aryl Grignard reagents with a surveyed titanate, were reacted with 2 under the conditions previously used for Fe-catalyzed oxidative arylation of benzamides . The ipso arylation of Ti group leading to 4 is supposed to involve an Fe/Ti exchange reaction, and the resulting Fe intermediate undergoes an ortho C–H arylation of the amide group .…”