Combining Fluorous and Triazole Moieties for the Tagging of Chiral Azabis(oxazoline) Ligands
作者:Ramesh Rasappan、Tobias Olbrich、Oliver Reiser
DOI:10.1002/adsc.200900129
日期:——
New fluorous-tagged azabis(oxazoline) ligands were prepared using the copper-catalyzed azide-alkyne cycloaddition as ligation method. The resulting ligands were tested in copper-catalyzed asymmetric benzoylations (up to 99% ee), nitroaldol (up to 90% ee), and Michael reactions (up to 82% ee). The combination of unpolar fluorinated alkyl chains and polar triazolemoieties imposes properties that are
Sidearm Effect: Improvement of the Enantiomeric Excess in the Asymmetric Michael Addition of Indoles to Alkylidene Malonates
作者:Jian Zhou、Yong Tang
DOI:10.1021/ja026936k
日期:2002.8.1
A pseudo-C3-trisoxazoline was designed and synthesized. The improvement of the traditional bisoxazoline into a novel trisoxazoline by a sidearm approach resulted in highly catalytic enantioselective Michael addition of indoles to alkylidene malonates. Excellent catalytic reactivity and enantioselectivity (up to 99% yield and 93% ee) were achieved.
Polystyrene-supported cu(II)-R-Box as recyclable catalyst in asymmetric Friedel–Crafts reaction
作者:V. G. Desyatkin、M. V. Anokhin、V. O. Rodionov、I. P. Beletskaya
DOI:10.1134/s1070428016120010
日期:2016.12
complex of copper(II) trifluoromethanesulfonate with chiral isopropyl bis(oxazoline) ligand (i-Pr-Box) was immobilized on accessible and inexpensive Merrifield resin according to a “click” procedure. The resulting catalyst showed high efficiency and recyclability in the asymmetricFriedel–Craftsalkylation of indole and its derivatives. The catalyst can be recycled five times without appreciable loss in
Enantioselective Friedel–Crafts reaction of indoles with arylidene malonates catalyzed by<sup>i</sup>Pr-bisoxazoline–Cu(OTf)<sub>2</sub>
作者:Jian Zhou、Yong Tang
DOI:10.1039/b313197a
日期:——
The cheap and simple iPr-bisoxazolineâCu(OTf)2 proves to be an efficient catalyst in the asymmetric FriedelâCrafts reaction of indole with arylidene malonates. In iBuOH, the S-enantiomer was obtained in up to 97% ee, while the opposite enantiomer was obtained in up to 78% ee in CH2Cl2 or TTCE.
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