Asymmetric conjugate additions to 1,1′-diactivated cyclic enones—a comparative study
摘要:
A study of copper-phosphoramidite-catalysed ZnR2 and AlR3 additions to 1,1'-dicarbonyl-activated cyclic Michael acceptors has revealed high enantioselectivities for AlR3 (R = Me, Et) 1,4-addition to a range of 3-acylcoumarins (85-98% ee, trans:cis similar to 90:10) using commercial OF readily available ligands. Large substituents at the 6-position, and to some extent at the 5-position, of the coumarin are less well tolerated, nor is truncation of the coumarin motif to a comparable 2-acylcyclohexenone (ee values up to 78%). (C) 2009 Elsevier Ltd. All rights reserved.
Asymmetric conjugate additions to 1,1′-diactivated cyclic enones—a comparative study
作者:Xiaoping Tang、Alexander J. Blake、William Lewis、Simon Woodward
DOI:10.1016/j.tetasy.2009.07.006
日期:2009.8
A study of copper-phosphoramidite-catalysed ZnR2 and AlR3 additions to 1,1'-dicarbonyl-activated cyclic Michael acceptors has revealed high enantioselectivities for AlR3 (R = Me, Et) 1,4-addition to a range of 3-acylcoumarins (85-98% ee, trans:cis similar to 90:10) using commercial OF readily available ligands. Large substituents at the 6-position, and to some extent at the 5-position, of the coumarin are less well tolerated, nor is truncation of the coumarin motif to a comparable 2-acylcyclohexenone (ee values up to 78%). (C) 2009 Elsevier Ltd. All rights reserved.
A Benzannulation Strategy for Rapid Access to Quinazoline-2,4-diones via Oxidative N-Heterocyclic Carbene Catalysis
作者:Arghya Ghosh、Sayan Shee、Akkattu T. Biju
DOI:10.1021/acs.orglett.2c00954
日期:2022.4.15
benzannulation of enals with suitably substituted pyrimidine-2,4-diones allowing the mild and facilesynthesis of functionalized quinazoline-2,4-diones is presented. This oxidative transformation proceeds via the simultaneous generation of dienolates and α,β-unsaturated acylazoliums and follows a vinylogous Michael/aldol/β-lactonization/decarboxylation/oxidation sequence to afford quinazoline-2,4-diones