Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

Abstract

Cascade cyclocarbopalladation of the readily available aryl/alkyl-substituted propargylic amides containing an aryl iodide moiety, followed by Suzuki–Miyaura coupling with arylboronic acids, allowed an efficient regio- and stereoselective synthesis of tetrasubstituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones. Moreover, cascade cyclocarbopalladation, followed by the reaction with 2-alkynyltrifluoroacetanilides, accomplished a double cyclization to afford challenging 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones bearing a 3-indolyl substituent through aminopalladation/reductive elimination.

One-Pot CuI/DBU-Catalyzed Carboxylative Cyclization toward Oxazolidinones Using Recyclable Molecular Sieves as Efficient Promoters for Fixation of CO2 in Water Medium

“…Interestingly, when the reaction was performed in the presence of the bulky bases such as DBU (entries 7–9), no compound 4 was observed after 24 h. These results also provide evidence that compound 5 not only was obtained from compound 4 but also could be obtained directly from compounds 1 , 2 , and 3 . Hence, DBU was selected as the appropriate base for this carboxylative cyclization reaction. , …”

“…Hence, DBU was selected as the appropriate base for this carboxylative cyclization reaction. 36,37 To prove the role of MS in this reaction, an absorption measurement was made using a simple set-up shown in Figure S1a, where the amount of CO 2 absorbed by the solution was estimated from the volume change in the syringe. Three conditions, with only H 2 O, MS/H 2 O, and MS/H 2 O/DBU, respectively, were used with an absorption time of 5 h. It was measured to be 0.5 mL for H 2 O only, 4.5 mL for H 2 O-soaked MS, and 5.8 mL for H 2 O/DBU-soaked MS.…”

Stereoselective Construction of Unsymmetrically Linked Heterocycles via Palladium-Catalyzed Alkyne Insertion/Cycloimidoylation Cascade

“…In this regard, palladium-catalyzed cascade reactions were proven to be powerful strategies . However, the direct catalytic assembly of unsymmetrically olefinic linked such heterocycles remains limited …”