TY - JOUR

T1 - Unexpected formal [4 + 2]-cycloaddition of chalcone imines and homophthalic anhydrides

T2 - preparation of dihydropyridin-2(1H)-ones

AU - Guranova, Natalia

AU - Golubev, Pavel

AU - Bakulina, Olga

AU - Dar'in, Dmitry

AU - Kantin, Grigory

AU - Krasavin, Mikhail

N1 - Publisher Copyright: © The Royal Society of Chemistry 2021. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/5/7

Y1 - 2021/5/7

N2 - A series of medicinally important dihydropyridin-2(1H)-ones have been preparedviaa novel [4 + 2]-formal cycloaddition reaction of chalcone imines and homophthalic anhydrides, which is a rare example of lactam construction from an imine acting as a four-atom building block. In contrast to previous studies on the reactivity of homophthalic anhydrides towards similar substrates,N-tosyl chalcone imines, we found the possibility of switching chemoselectivity by changing substituents at the nitrogen atom, which leads to the formation of heterocycles instead of the expected carbocycles. This reaction is very similar in appearance to the classic 1,2-addition of cyclic anhydrides to imines, often referred to as the Castagnoli-Cushman reaction, but differs in mechanistic details (representing a 1,4-reaction of imine). The developed atom-economical, stereoselective and catalyst- and chromatography-free protocol provided facile access to 28 structurally diverse heterocyclic products (in up to 88% yield) including synthetically challenging annelated tricyclic and previously unreported pentaaryl-substituted dihydropyridin-2(1H)-ones.

AB - A series of medicinally important dihydropyridin-2(1H)-ones have been preparedviaa novel [4 + 2]-formal cycloaddition reaction of chalcone imines and homophthalic anhydrides, which is a rare example of lactam construction from an imine acting as a four-atom building block. In contrast to previous studies on the reactivity of homophthalic anhydrides towards similar substrates,N-tosyl chalcone imines, we found the possibility of switching chemoselectivity by changing substituents at the nitrogen atom, which leads to the formation of heterocycles instead of the expected carbocycles. This reaction is very similar in appearance to the classic 1,2-addition of cyclic anhydrides to imines, often referred to as the Castagnoli-Cushman reaction, but differs in mechanistic details (representing a 1,4-reaction of imine). The developed atom-economical, stereoselective and catalyst- and chromatography-free protocol provided facile access to 28 structurally diverse heterocyclic products (in up to 88% yield) including synthetically challenging annelated tricyclic and previously unreported pentaaryl-substituted dihydropyridin-2(1H)-ones.

UR - http://www.scopus.com/inward/record.url?scp=85105520658&partnerID=8YFLogxK

U2 - 10.1039/d1ob00534k

DO - 10.1039/d1ob00534k

M3 - Article

C2 - 33949583

AN - SCOPUS:85105520658

VL - 19

SP - 3829

EP - 3833

JO - Organic and Biomolecular Chemistry

JF - Organic and Biomolecular Chemistry

SN - 1477-0520

IS - 17

ER -