Modification of Pseudo-C3-Symmetric Trisoxazoline and Its Application to the Friedel-Crafts Alkylation of Indoles and Pyrrole with Alkylidene Malonates
New pseudo-C3-symmetric hetero-trisoxazoline can be easily prepared on a gram scale in good yield. Its combination with copper(II) triflate exhibits high enantiomeric induction in the asymmetric Friedel-Crafts alkylation between indoles and alkylidene malonates, with up to 97% ee and good to excellent yields. The catalyst loading can be lowered to 0.5 mol% without loss of the enantiomeric excess.
Malonate-type bis(oxazoline) ligands with sp2 hybridized bridge carbon: synthesis and application in Friedel–Crafts alkylation and allylic alkylation
作者:Hongliang Chen、Fengpei Du、Lei Liu、Jing Li、Qiuying Zhao、Bin Fu
DOI:10.1016/j.tet.2011.09.106
日期:2011.12
the Friedel–Crafts reaction and allylicalkylation. The Cu(II) complex of ligand 4b bearing the benzyl group afforded good to excellent enantioselectivity for the F–C adducts (up to >99% ee) between indole and alkylidene malonate, and the palladium complex of ligand 4c bearing the phenyl group afforded excellent enantioselectivity (up to 94% ee) for the allylicalkylation product.
Synthesis of New C2- Symmetric Fluoren-9-ylidene Malonate Derived Bis(oxazoline) Ligands and Their Application in Friedel-Crafts Reactions
作者:Jing Li、Hong-Liang Chen、Lei Liu、Bin Fu
DOI:10.3390/molecules15128582
日期:——
series of new C(2)-symmetric fluoren-9-ylidene malonate-derived bis(oxazoline) ligands were synthesized from fluoren-9-ylidene malonate and enantiomerically pure amino alcohols via a convenient route. Their asymmetric catalytic properties in the Friedel-Crafts reactions of indoles with arylidene malonates were evaluated, and the Cu(OTf)2 complex of a fluoren-9-ylidene malonate-derived bis(oxazoline) bearing
Mechanochemical Copper‐Catalyzed Asymmetric Michael‐Type Friedel–Crafts Alkylation of Indoles with Arylidene Malonates
作者:Plamena Staleva、José G. Hernández、Carsten Bolm
DOI:10.1002/chem.201901826
日期:2019.7.11
asymmetric Michael‐type Friedel–Crafts alkylation of indoles with arylidene malonates was developed. The reaction proceeds under ambient atmosphere using a chiral bis(oxazoline)copper catalyst in a mixer mill. Under these reaction conditions nineteen 3‐substituted indolederivatives were synthesized in good to excellent yields (up to 98 %), and with good enantioselectivities (up to 91:9 e.r.) after short milling
Dependence of Enantioselectivity on the Ligand/Metal Ratio in the Asymmetric Michael Addition of Indole to Benzylidene Malonates: Electronic Influence of Substrates
Simple bis(oxazoline) ligands, especially azabis(oxazolines), can promote the copper(II)-catalyzed Michaeladdition of indoles to benzylidenemalonates with up to >99 % ee (ee=enantiomeric excess), provided that the ligand/metalratio is tuned meticulously with particular regard to the electronic properties of the substrate. Despite a common paradigm followed in many asymmetric catalyses, an excess