Showing papers on "Benzopyrans published in 2018"
TL;DR: A novel and efficient asymmetric synthesis of 2,4-diaryl-1-benzopyrans via enantioselective decarboxylative alkylation of β-keto acids to o-QM intermediates, followed by sequential cyclization and dehydration, has been developed.
64 citations
TL;DR: An efficient and novel rhodium-catalyzed transannulation of N-sulfonyl-1,2,3-triazoles with in situ generated o-quinone methides from 2-hydroxybenzyl alcohols has been achieved for the synthesis of substituted benzopyrans in good yields.
57 citations
TL;DR: Various benzoxazonines were synthesized through a formal [7 + 2] cycloaddition of arynes with N-vinyl-α,β-unsaturated nitrones under mild conditions to access useful building blocks with specific stereoselectivity.
26 citations
05 Dec 2018
TL;DR: 4-Vinylphenyl-substituted squaramides have been tested as organocatalysts for the diastereo- and enantioselective synthesis of trisubstituting benzopyrans via an oxa-Michael intramolecular nitro-Michael cascade reaction.
Abstract: 4-Vinylphenyl-substituted squaramides have been tested as organocatalysts for the diastereo- and enantioselective synthesis of trisubstituted benzopyrans via an oxa-Michael intramolecular nitro-Michael cascade reaction. Both the enantio- and diastereoselection were good to moderate, depending on the nature of the chiral scaffold in the catalyst. The diastereoselection is better for the most active catalyst because the final products epimerize at C-3 along the time. Supported squaramide sq-9 prepared by copolymerization of sq-4 with styrene and divinylbenzene is also effective in promoting the cascade reaction, and it is recoverable and reusable for five cycles maintaining the activity.
7 citations
TL;DR: In this paper, the radical cyclization reactions of cyclic 1,3-dicarbonyl compounds and α,β-unsaturated alcohols through Mn(OAc)3 were performed.
3 citations
Patent•
16 Nov 2018
TL;DR: The benzopyrans compound provided by the invention is simple in structure, easy to synthesize, low in production cost, and has a good inhibiting effect on the strawberry botrytis cinerea, potato altemaria solani, and watermelon fusarium oxysporum.
Abstract: The invention relates to the field of the agricultural fungicide, and specifically relates to a benzopyrans compound as well as a preparation method and application thereof. The benzopyrans compound provided by the invention is simple in structure, easy to synthesize, low in production cost, and has a good inhibiting effect on the strawberry botrytis cinerea, potato altemaria solani, and watermelon fusarium oxysporum.