Directed C8–H allylation of quinoline N-oxides with vinylcyclopropanes via sequential C–H/C–C activation

Abstract

The Rh(III)-catalyzed C8-allylation of quinoline N-oxides has been accomplished using vinylcyclopropanes as an allyl source with excellent diastereoselectivity at room temperature. The C-H/C-C activation, substrate scope and natural product mutation...

Cp*IrIII-Catalyzed C8-Selective C–H Activation Enables Room-Temperature Direct Arylation of Quinoline N-Oxides with Arylsilanes

“…In 2017, Chang and co-workers reported that a Cp*Ir catalyst, assisted with a catalytic amount of Cu­(OAc) 2 , exhibits excellent catalytic performance for C–H arylation of a series of phenyl amides under mild conditions, possibly because this process involves an oxidatively induced reductive elimination, which requires a lower reaction energy, so that this C–H functionalization can be carried out at room temperature . To the best of our knowledge, there is no report on Ir-catalyzed C–H arylation of quinoline N -oxides at the C 8 -position with arylsilanes under mild conditions . In this paper, we report a Cp*Ir-catalyzed C–H arylation of quinoline N -oxides at room temperature in good yields.…”

A redox-neutral weak carbonyl chelation assisted C4–H allylation of indoles with vinylcyclopropanes

“…7 In this context, readily accessible three-membered vinylcyclopropanes (VCPs) can serve as a versatile synthon for the direct step and atom-economical transformations through ring expansion via C–C bond cleavage. 8 Hence, integrating C–H activation with C–C bond cleavage 9 in a sequence would be valuable. More recently, the Ackermann 8 b and Glorius 8 c groups have accomplished the C2–H allylation of indoles with VCPs utilizing 2-pyridyl DG in the presence of Co and Mn-catalysis, respectively (Scheme 1B).…”

Site-Selective C8-Alkylation of Quinolines with Cyclopropanols: Merging C–H/C–C Bond Activation

“…Substituted quinolines represent key skeletons in drug discovery and synthetic and material sciences . Consequently, the development of effective methods for their synthetic elaboration has been marked as an important research topic . In the past few years, a number of seminal studies showed that a broad range of C2–H functionalizations of quinolines can readily be achieved due to the inherent reactivity of the C–N bond .…”

“…In contrast, the functionalization of the less reactive C8–H bond, which can be accomplished utilizing quinoline N -oxide as the substrate via the formation of a five-membered metallacycle, remains synthetically challenging. , However, most of these transformations have been performed employing the rare second and third row transition metal catalysts (Rh, Ir, Pd, Ru etc. ), whereas a few studies focused on using the first row metals . In view of the synthetic modification of quinoline, C8-alkylation reactions have recently been investigated intensively due to their potential applications. ,, These alkylation reactions were realized by employing coupling partners such as activated and unactivated alkenes, alkynes, and carbenes (Scheme a) .…”

“…), whereas a few studies focused on using the first row metals . In view of the synthetic modification of quinoline, C8-alkylation reactions have recently been investigated intensively due to their potential applications. ,, These alkylation reactions were realized by employing coupling partners such as activated and unactivated alkenes, alkynes, and carbenes (Scheme a) . Despite these developments, there has been a great surge to explore new alkylating agents to meet the synthetic diversity.…”