Palladium-catalyzed denitrative N-arylation of nitroarenes with pyrroles, indoles, and carbazoles

Abstract

We have developed an efficient palladium-catalyzed denitrative N-arylation via cross-coupling of N–H heteroarenes with nitroarenes, one of the most inexpensive and fundamental feedstocks in the chemical industry. A variety of...

Palladium-catalyzed C–Si bond formation via denitrative cross-coupling of nitroarenes with hexamethyldisilane

“…On the basis of previous reports and our present studies, 12–16 a plausible mechanism is proposed and illustrated in Scheme 4. The catalytic cycle of the reaction commences with η 2 -arene complex II species derived from the π-coordination of nitroarene 1 and Pd(0) complex I , which is generated by Pa(acac) 2 with BrettPhos in situ .…”

“…Inspired by the works of denitrative functionalizations 12–16 and C(sp 2 )–Si bond formations, 6,8 we started our investigation by using 4-nitroanisole ( 1a ) and hexamethyldisilane ( 2 ) as the model substrates. The Pd(acac) 2 /BrettPhos, 17 which showed relatively high catalytic efficiency in denitrative functionalizations, 12–16 was initially employed in this denitrative silylation reaction. To our delight, this catalyst is effective for the transformation.…”

“…In 2017, Nakao and Sakaki made a landmark advance for palladium-catalyzed denitrative Suzuki–Miyaura type coupling, 12 in which the oxidative addition of the Ar–NO 2 bond to the palladium center was observed for the first time. Since then, Nakao, Yamaguchi, You, and others have successively developed transition-metal-catalyzed denitrative C–C, 13 C–N, 14 C–H, 15 and C–O 16 bonds formation via the cleavage of the C(sp 2 )–NO 2 bond. However, the construction of the C–Si bond via denitrative cross-coupling of nitroarene remains an unresolved challenge.…”

Reductive Arylation of Nitroarenes with Chloroarenes: Reducing Conditions Enable New Reactivity from Palladium Catalysts

“…Instead, palladium-catalyzed crosscouplings of nitroarenes feature C−NO 2 oxidative addition (Scheme 2B). 36−40 Herein, we demonstrate how the same palladium catalysts that favor C−NO 2 oxidative addition and promote C−N bond formation with amines 39,40 reveal new reactivity when subjected to reducing conditions: catalyzing the N-arylation of azoarenes via an association-reductive palladation sequence. The N-functionalization of azoarenes using arylpalladium(II) intermediates is notable because the N�N bond of azoarenes is generally considered inert toward arylpalladium(II) intermediates, 41 even functioning as a useful directing group for C− H bond activation.…”

“…In contrast to nickel, palladium-catalyzed reductive arylation or acylation of nitroarenes is unknown. Instead, palladium-catalyzed cross-couplings of nitroarenes feature C–NO 2 oxidative addition (Scheme B). − …”