Imidazol-5-one as an Acceptor in Donor–Acceptor Cyclopropanes: Cycloaddition with Aldehydes
Andrey А. Mikhaylov, Андрей В. Кулешов, Pavel N. Solyev, Аlexander А. Korlyukov, Павел В. Дороватовский, Константин С. Минеев, Михаил С. Баранов
Abstract
Spiro[imidazol-5-one-4,1'-cyclopropanes] behave as donor-acceptor (D-A) cyclopropanes in a formal cycloaddition reaction with aldehydes. The activation of such type of cyclopropanes is achieved with an equivalent of Brønsted acid. The reaction proceeds in high yields of 51-92% and demonstrates moderate diastereoselectivity at the quaternary stereocenter, which is determined by the electron-donating nature of the aldehyde partner. The ease of separation of stereoisomers allowed the creation of a library of 44 spiroannulated tetrahydrofurans with various substitution patterns.
Topics & Concepts
StereocenterChemistryCycloadditionAldehydeAcceptorBrønsted–Lowry acid–base theoryMedicinal chemistryStereochemistryCatalysisOrganic chemistryEnantioselective synthesisPhysicsCondensed matter physicsCyclopropane Reaction MechanismsCatalytic Alkyne ReactionsAsymmetric Synthesis and Catalysis