Hydroxyl directed <i>C</i>-arylation: synthesis of 3-hydroxyflavones and 2-phenyl-3-hydroxy pyran-4-ones under transition-metal free conditions
作者:Sayantan Paul、Asish K. Bhattacharya
DOI:10.1039/c7ob01929g
日期:——
Hydroxyl assisted, efficient, transition-metal free and direct C-arylation of 3-hydroxychromone and 5-hydroxy pyran-4-one moieties in the presence of a base, air as an oxidant and arylhydrazines as arylating agents to furnish highly biologically active 3-hydroxyflavones and 2-phenyl-3-hydroxy pyran-4-ones has been developed.
Enantioselective Catalytic Synthesis of α‐Stereogenic Chromen‐4‐one Amino Derivatives
作者:Ruslan A. Kovalevsky、Konstantin V. Vasechkin、Alexander S. Kucherenko、Sergei G. Zlotin
DOI:10.1002/adsc.202300659
日期:2023.9.19
Direct enantioselectivesynthesis of 2-substituted chromen-4-ones, bearing the amino group at α-stereogenic center with respect to the heterocycle is developed. It is based on Mannich-type asymmetric addition of 3-hydroxychromen-4-one and its analogues to N-protected imines in the presence of available alkaloid dihydrocuprein. α-Stereogenic chromenone amino derivatives were formed in this reactions
A Direct Organocatalytic Enantioselective Route to Functionalized
<i>trans</i>
‐Diels–Alder Products Having the Norcarane Scaffold
作者:Casper L. Barløse、Niklas L. Østergaard、René S. Bitsch、Marc V. Iversen、Karl Anker Jørgensen
DOI:10.1002/anie.202106598
日期:2021.8.9
organocatalysis with excellent selectivity, high yield and up to five contiguous stereocenters is presented. The reaction concept integrates the halogen effect and a novel discovered pseudo-halogen effect to direct an endo-selective, secondary-amine catalyzed Diels–Alder reaction allowing for the subsequent formation of trans-Diels–Alder cycloadducts featuring the norcarene scaffold. The methodology relies on