Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

Abstract

SummaryThis review highlights the development of palladium-catalyzed C–H and N–H functionalization reactions involving indole derivatives. These procedures require unactivated starting materials and are respectful of the basic principle of sustainable chemistry tied to atom economy.

Oxidative Alkenylation of Fused Bicyclic Heterocycles

“…The crosscoupling was achieved, using 3 equiv. of alkene in the presence of 2 mol-% of [(Cp*Rh(III)Cl 2 ) 2 ] as catalyst, 8 mol-% of AgSbF 6 as an additive and anhydrous Cu(OAc) 2 as oxidant in dioxane at 120°C. In a representative example, the natural product chromone 118 was treated by 1,4-naphthoquinone 128 under the reaction conditions cited above to lead to the desired final product 129 in 79 % yield (Scheme 53).…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The number of publications and books [16][17][18][19] in synthetic organic and medicinal chemistry has increased tremendously ( Figure 1) (fewer than 85 papers/year in 2000 and 2001 and more than 350 papers/year from 2014 to 2017). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The number of publications and books [16][17][18][19] in synthetic organic and medicinal chemistry has increased tremendously ( Figure 1) (fewer than 85 papers/year in 2000 and 2001 and more than 350 papers/year from 2014 to 2017).…”

“…The oxidative Heck-type reaction (also called Fujiwara-Moritani reaction, Mizoroki-Heck type reaction, oxidative alkenylation, oxidative vinylation, oxidative olefination, direct alkenylation, dehydrogenative coupling, dehydrogenative Heck coupling, direct alkenylation or oxidative CH/CH coupling) has emerged as one of the most powerful methods for carbon-carbon bond formation during the last two decades. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The number of publications and books [16][17][18][19] in synthetic organic and medicinal chemistry has increased tremendously ( Figure 1) (fewer than 85 papers/year in 2000 and 2001 and more than 350 papers/year from 2014 to 2017). This cross-coupling reaction has the advantage of being atom-economical, with a low chemical cost and less waste compared with traditional cross-coupling reactions such as direct alkenylation, Heck, Suzuki-Miyaura, Stille and Negishi (Scheme 1).…”

Aerobic Oxidative Functionalization of Indoles

“…[1] Early works in relation to indole functionalization focused on catalytic Friedel-Crafts alkylations including those with stereoselective control. [2] In 2012, Broggini et al disclosed a review which discussed the palladium-catalyzed dual CÀ H or NÀ H functionaliza-tion of unfunctionalized indole derivatives with alkenes and arenes, [3] and Larrosa and co-worker summarized C2 and C3 regioselective direct arylation of indoles. [4] In both reviews, few examples of indole functionalization by aerobic oxidation were given.…”

Transition Metal‐Catalyzed CH Activation of Indoles

“…Thea pproach has developed beyond simpler eactiond iscovery studies to be incorporated in the mainstream synthetic community,e xemplified by the increasing exploitation of C À Ha ctivation in the preparation of architecturally complicated indolecontainingn atural products and pharmaceutically importantmoieties. [20] Althoughareview [21] dedicated to C À Ha ctivation of the indole nucleus was published in 2012, only some facetso ft he literature were discussed andasignificantn umber of additional contributions has been revealed. In fact, over fifteen newa rticles were published concerning this very topic during the preparation of this manuscript, [22] clearly demonstrating the importance of this field and its emergence as afrontier in transitionm etal catalysis.…”