Manganese‐Catalyzed Direct Nucleophilic C(sp²)H Addition to Aldehydes and Nitriles

Abstract

Herein, a manganese-catalyzed nucleophilic addition of inert C(sp(2))-H bonds to aldehydes and nitriles is disclosed by virtue of a dual activation strategy. The reactions feature mild reaction conditions, excellent regio- and stereoselectivity, and a wide substrate scope, which includes both aromatic and olefinic C-H bonds, as well as a large variety of aldehydes and nitriles. Moreover, mechanistic studies shed light on possible catalytic cycles.

Re‐Catalyzed Annulations of Weakly Coordinating N‐Carbamoyl Indoles/Indolines with Alkynes via C−H/C−N Bond Cleavage

“…Remarkably,t he unique catalytic trios of Re 2 (CO) 10 / Me 2 Zn/ZnCl 2 and Re 2 (CO) 10 /[MeZnNPh 2 ] 2 /Zn(OTf) 2 described herein overcame the limitation of stoichiometric use of Me 2 Zn/ ZnBr 2 in our previousm anganese system, [7] which represented as ubstantial step towards more powerful Group 7m etal catalyst systems. The weakly coordinating and low electrophilicc arbamoyl group was used as an efficient directingg roup and reaction partner with CÀRe bond in rheniumc atalysis for the first time.…”

“…[4d,f] As far as we are aware,t here has been no example reported using weakly coordinating O-atom directing groups such as carbonyl in rhenium-catalyzed CÀHa ctivation reactions. [7] This powerful combination enabled the CÀHa ctivation of weakly coordinating ketones ubstrates and the thereafter addition of the CÀMn bond to simple aldehydes and imines,w hichw ere otherwise difficult to achievev ia other transition-metal catalysis. Thus, [3+ +2] annulations of indoles with alkynes have been achieved throughb oth CÀHa nd CÀNb ond cleavage.…”

Rh(III)‐Catalyzed Regioselective Acetylation of sp2 C−H Bond Starting from Paraformaldehyde

“…For instance, Wang and coworkers developed a palladium‐catalyzed direct acetylation of arylpyridines with diketobutane as an acetyl reagent in the presence of TBHP in 2012. Subsequently, Wang group disclosed an acetylation of arenes by a manganese‐catalyzed C−H activation and synergetic utilization of Me 2 Zn and ZnBr 2 . In 2016, Xie described a Rh−Cu bimetallic catalyzed o ‐acetylation of acyloxacetamide with 2‐butyne (Scheme a).…”

Recent Advances of Manganese Catalysis for Organic Synthesis

“…Under photoirradiation, this catalyst was shown to borylate benzene and pentane in good and moderate yields (with respect to B 2 Pin 2 ), respectively. [74] The substrate scope of the reaction was also improved with a range of aldehydes, arenes and directing groups tolerated. [73] The addition of HSiEt 3 allowed the regeneration of the active cata- This methodology was expanded by Wang, by enabling the reaction to proceed without the need for silane by instead using a Lewis acid (Scheme 41).…”