In(OTf)₃‐Catalyzed Tandem Nucleophilic Addition and Cyclization of ortho‐Alkynylarylaldimines to 1,2‐Dihydroisoquinolines

Abstract

Doppelkatalysator: Eine In(OTf)3‐katalysierte Tandemanellierung führt in hohen Ausbeuten zu 1,2‐Dihydroisochinolinen. Der Katalysator aktiviert die Imin‐ und die Alkingruppe für die Addition von Nucleophilen und anschließende intramolekulare Cyclisierung (siehe Schema; OTf=Trifluormethansulfonat).

Chiral Silver Phosphate Catalyzed Transformation of ortho‐Alkynylaryl Ketones into 1H‐Isochromene Derivatives through an Intramolecular‐Cyclization/Enantioselective‐Reduction Sequence

“…We then explored the use of other additives to improve the enantioselectivity of the reaction ( Table 2, entries 8-10). [14] To verify the order of the reaction sequence, we conducted a control experiment with alcohol 6 as a possible intermediate (Scheme 2). In particular, a considerable reduction in both the chemical yield and the ee value was observed in the presence of 4 MS.…”

Concise One‐Pot Tandem Synthesis of Indoles and Isoquinolines from Amides

“…To simplify the method, a simultaneous procedure was examined. When a solution of 1 a in DCB, in the presence of PhI(OAc) 2 , PtCl 2 , and ethanol, was heated at 100 8C, 2 a was produced in 85 % yield without a decrease in the reactivity of PtCl 2 ( metal catalysts, some of which were used in previous studies for intramolecular cyclization of 2-alkynylaniline derivatives, [1][2][3] did not give satisfactory results (Table 1, entries 5-9). Having established optimal reaction conditions, we examined the scope of the reaction for various 2-alkynylbenzamides 1 a-1 i ( Table 2).…”

ChemInform Abstract: Chiral Silver Phosphate Catalyzed Transformation of ortho‐Alkynylaryl Ketones into 1H‐Isochromene Derivatives Through an Intramolecular‐Cyclization/Enantioselective‐Reduction Sequence.

“…However, the same product would be obtained if the reactions occurred in the reverse order, that is, reduction to the alcohol, followed by cyclization. [14] To verify the order of the reaction sequence, we conducted a control experiment with alcohol 6 as a possible intermediate (Scheme 2). When compound 6 was subjected to the catalytic reaction under the influence of Ag[(R)-1 a] (10 mol %) without the Hantzsch ester, the reaction proceeded with very low conversion, even after 6 h, and product 5 a of 5-exo cyclization was obtained in 10 % yield, whereas almost none of the desired 6-endo cyclization product 4 a was observed.…”