Herein, we demonstrated a silver/KSO-mediated highly regio- and diastereoselective 6/5- trig radical cascade cyclization of alkyne-tethered cyclohexadienones with sulfonyl hydrazides or sodium sulfinates and subsequent selenation to access 6,6-dihydrochromenone and 6,5-fused tetrahydro benzofuranone derivatives. This reaction protocol features high functional group compatibility and has a wide substrate scope providing a variety of dihydrochromenones and tetrahydro benzofuranone derivatives in good to excellent yields. The reaction proceeds via the attack of a sulfonyl radical to alkyne over the activated Michael acceptor.
View Article and Find Full Text PDFA 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.
View Article and Find Full Text PDFHerein, 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.
View Article and Find Full Text PDFA 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.
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