Synthesis of Indenopyridine Derivatives via MgI₂‐Promoted [2+4] Cycloaddition Reaction of In‐situ Generated 2‐Styrylmalonate from Donor‐Acceptor Cyclopropanes and Chalconimines

Abstract

An unexpected MgI 2 -promoted [2 + 4] cycloaddition reaction of in-situ generated 2-styrylmalonate from donor-acceptor cyclopropanes with chalconimines to synthesize highly substituted indenopyridine derivatives under the mild reaction conditions have been developed. Additionally, these derivatives were utilized for the synthesis of highly substituted 9-membered lactam by oxidative C=C bond cleavage and spiro [oxoindane-pyrrolidine] derivative via Meinwald type rearrangement.

Donor–Acceptor Cyclopropanes as an Expedient Building Block Towards the Construction of Nitrogen‐Containing Molecules: An Update

“…Very recently, our group achieved an MgI 2 ‐promoted [2+4] cycloaddition reaction of 2‐styrylmalonates 135 (generated in situ from DACs 3 ) with chalconimines 136 to construct highly substituted indenopyridine derivatives 137 (Scheme ) . The reaction took place under mild conditions and showed a wide substrate scope.…”

Formal insertion of selenoketenes into donor–acceptor cyclopropanes: mesomeric alkynylselenolates as key starting materials

“…Thus, these strained ring systems display various reactivities such as (3 + n)-cycloadditions, 3 rearrangements 4 and ring-opening reactions. 5 Highly functionalized, saturated or partially saturated four-, five-, six- or seven-membered rings are furnished by various (3 + n)-cycloaddition reactions of D–A cyclopropanes with π-systems such as carbonyls, 6 imines, 7 nitrosoarenes, 8 nitrones 9 and polarized hetero-2π-components. 10 However, cumulated π-systems have not been extensively explored as reaction partners with D–A cyclopropanes.…”

Lewis Acid‐Catalyzed Formal (4+2)‐ and (2+2+2)‐Cycloaddition Between 1‐Azadienes and Styrylmalonates as Analogues of Donor‐Acceptor Cyclopropanes

“…Moreover, the type of substrate and catalyst has a dramatic effect on regioselectivity; for example, substrates with neither an α‐substituent nor a rigidly fixed C(2)−C(3) bond showed a tendency for the (3+2)‐addition of a 1,3‐zwitterion generated from an ACDC at C=N or C=C double bond of the starting azadiene (Scheme 1). Among them, reactions of only one type occurred with full involvement of the azadiene system to give (4+2)‐cycloaddition products (tetrahydropyridines) via styrylmalonates generated in situ from ACDCs [11b] …”