Markovnikov‐Selective Palladium Catalyst for Carbonylation of Alkynes with Heteroarenes

Abstract

An ew class of palladium catalysts,b ased on heterocyclic diphosphines,was rationally designed and synthesized. Application of one of these catalysts allows novel Markovnikov-selective carbonylation of non-activated alkynes with heteroarenes to give the corresponding branched a,bunsaturated ketones in excellent yields (up to 97 %) and regioselectivities (b/l up to 99:1). In addition to heteroarenes, other common nucloephiles (alcohol, phenol, amine,a nd amide) furnish the desired carbonylation products smoothly in high yields. Scheme 1. a) Ligand modification and b) design of DPMPhos ligands. Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.Scheme 5. Synthetisis of substituted cyclopentanones in one pot. [a] At 90 8 8Cins tep 1. [b] With 10 mol % p-TsOH instead of HOTfinstep 2. Tf = trifluoromethanesulfonyl. Scheme 6. Synthetisis of g-keto ester.

Catalytic Functionalization of C–H Bonds of Azulene by Carbene/Nitrene Incorporation

“…8 The functionalization of C−H bonds at the 5-membered ring and, particularly, the formation of carbon−carbon bonds, is relevant for subsequent uses of the modified azulene. Scheme 1 contains representative examples of such metal-catalyzed processes, showing arylation (a), 9 alkylation (b), 10 alkenylation (c), 11 alkynylation (d), 12 propargylation (e), 13 and carbonylation (f) 14 reactions. On the other hand, direct amination of azulene C−H bonds has been scarcely reported, mainly following the stoichiometric Vicarious nucleophilic substitution of hydrogen 15 (Scheme 1g), photoinduced aminations involving N-centered radicals, 16 or preparation of azo derivatives.…”

Recent Advances in the Functionalization of Azulene Through Pd‐Catalyzed Cross‐Coupling Reactions

“…Unique Markovnikov‐selective carbonylation of non‐activated alkynes 287 with azulene 1 produced the unsaturated ketone 289 in 71 % yield and regioselectivities (up to 99 : 1) using a new type of palladium catalyst based on heterocyclic diphosphines 288 (Scheme 109). [119] …”

External oxidant-compatible phosphorus(III)-directed site-selective C–H carbonylation

“…Typically, C-H carbonylation of Nprotected indoles can selectively generate C3 carbonyl indoles (Fig. 1B, top) (27)(28)(29)(30)(31). Recently, several groups have also achieved the siteselective C-H carbonylation of indoles at the C2position, (32)(33)(34)(35)(36), especially by the CO insertion, with the aid of directing groups at the N atom (Fig.…”