Showing papers on "Benzopyrans published in 2017"
TL;DR: The reaction was discovered while investigating a two-component strategy using 2-(hydroxy(phenyl)methyl)phenols to access the desired ortho-quinone methide in a Diels-Alder condensation to afford benzopyrans in good yields and selectivities.
42 citations
TL;DR: An efficient organocatalytic method for the asymmetric preparation of benzopyran- and benzofuran-fused polycyclic acetals is described for the first time and includes an interesting tunable Michael–acetalization of nitrostyrenes or α-aromatization–acetals of quinones.
Abstract: An efficient organocatalytic method for the asymmetric preparation of benzopyran- and benzofuran-fused polycyclic acetals is described for the first time. This useful approach includes an interesting tunable Michael–acetalization of nitrostyrenes or α-aromatization–acetalization of quinones. Under mild conditions, simple cyclic hemiacetals could be stereoselectively converted into four different types of polyheterocycles that serve as scaffolds for a number of bioactive natural products.
24 citations
TL;DR: In this paper, a mild and efficient method was developed for the preparation of tetrahydrobenzo[b]pyrans through a one-pot three-component condensation of aldehydes, malononitrile and dimedone in the presence of silica supported dual acidic ionic liquid (DAIL@SiO2) as a powerful catalyst under solvent-free conditions.
Abstract: Abstract A mild and efficient method was developed for the preparation of tetrahydrobenzo[b]pyrans through a one-pot three-component condensation of aldehydes, malononitrile and dimedone in the presence of silica supported dual acidic ionic liquid (DAIL@SiO2) as a powerful catalyst under solvent-free conditions. This procedure is characterized by mild reaction conditions, simple workup and environmental friendliness. Moreover, the catalyst could be recycled for five times with only a slight loss of catalytic activity.
9 citations
TL;DR: In this paper, a 2-aryl 1,3-dicarbonyl substrates were explored in an efficient and facile enolate-directed C‒H alkenylation process using readily available electron-deficient alkenes.
3 citations