Silver Ions Promoted Palladium-Catalyzed Inactive β-C(sp)-H Bond Arylation in Batch and Continuous-Flow Conditions.

A palladium(II)-catalyzed protocol for inactive β-C(sp)-H bond functionalization has been first accomplished. The reaction proceeds through five-membered carbocycles for the formation of C-C bonds the Pd(II)/Pd(IV) cycle. This reaction was carried out with various aryl iodides and benzothiazoles/benzoxazoles/benzimidazoles, which were well-tolerated in this reaction and successfully generated β-C(sp)-H arylated products.

Regioselective C-3-alkylation of quinoxalin-2(1)-ones C-N bond cleavage of amine derived Katritzky salts enabled by continuous-flow photoredox catalysis.

An efficient, transition metal-free visible-light-driven continuous-flow C-3-alkylation of quinoxalin-2(1)-ones has been demonstrated by employing Katritzky salts as alkylating agents in the presence of eosin-y as a photoredox catalyst and DIPEA as a base at room temperature. The present protocol was accomplished by utilizing abundant and inexpensive alkyl amine (both primary and secondary alkyl) and as well as this a few amino acid feedstocks were converted into their corresponding redox-active pyridinium salts and subsequently into alkyl radicals. A wide variety of C-3-alkylated quinoxalin-2(1)-ones were synthesized in moderate to high yields.

Visible-Light-Induced Deaminative Alkylation/Cyclization of Alkyl Amines with -Methacryloyl-2-phenylbenzoimidazoles in Continuous-Flow Organo-Photocatalysis.

Herein, we present a metal-free visible-light-induced eosin-y-catalyzed deaminative strategy for the sequential alkylation/cyclization of -methacryloyl-2-phenylbenzoimidazoles with alkyl amine-derived Katritzky salts, which provides an efficient avenue for the construction of various benzo[4,5]imidazo[2,1-]isoquinolin-6(5)-one derivatives in moderate to excellent yields under mild reaction conditions. The key enabling feature of this novel reaction includes utilization of redox-active pyridinium salts from abundant and inexpensive primary amine feedstocks that were converted into alkyl radicals via C-N bond scission and subsequent alkylation/cyclization with -methacryloyl-2-phenylbenzoimidazoles by the formation of two new C-C bonds. In addition, we implemented this protocol for a variety of amino acids, affording the products in moderate yields.

Cationic Pd(IV)-Induced Highly Diastereoselective Arylative Cascade Cyclization of Allene-Tethered Cyclohexadienones Leading to Oxygenated Bicyclic Motifs.

A cationic Pd(IV)-catalyzed arylative hydroxylation-Micheal addition of allenyl-tethered cyclohexadienones was developed. This relay reaction could afford highly diastereoselective various functionalized arylative 1,4-dioxane -bicyclic structural units with good to high yields. The striking features revealed from these studies is the necessity of Selectfluor and the oxidative hydroxylation originating from water initiated by F-Pd(IV) catalysis.