4 / 26
allied
academies
Journal of Biotechnology and Phytochemistry
Volume 1 Issue 3
Chemistry World 2017
Notes:
Page 56
November 13-15, 2017 Athens, Greece
7
th
World Congress on
Chemistry
Copper-guanidine catalyzed asymmetric allylic
alkynylation under phase transfer conditions
Xi-Yang Cui, Yicen Ge, Huan Jiang
and
Choon-Hong Tan
Nanyang Technological University, Singapore
F
orging a more intense link between transition metal catalysis
and asymmetric ion-pairing catalysis are recently purchased
by us. Enantiopure skipped 1, 4-enynes are useful building
blocks due to its transformability. In this work, enantioselective
alkynylation of cyclic allylic bromides was achieved due to an in
situ-generated guanidinium cuprate ion pair. Thus, enantiopure
cyclic 1,4-enynes were obtained by the first time through a
proposed distinct dynamic kinetic pathway, not common SN2’
pathway. In the presence of catalytic amount of copper(I) salt
and cyclic-guanidinium(CG), the asymmetric Csp–Csp3 bonds
were formed via alkynylation of racemic cyclic bromides with
aid of K
2
CO
3
as a base at room temperature. Various terminal
alkynes with different substituents on an aryl group and different
functional groups such as ester, amide, silyl, amine, hydroxyl, and
thioether are all suitable under the standard reaction condition.
The enantiospecific derivatization of products demonstrated
the practicability of this methodology. The mechanism study
revealed that alkynide in this Cu-catalyzed reaction behaves
as ‘hard’ nucleophile; a model ion-pairing catalysis which
was characterized by X-ray analysis and 1H-NMR and;
meanwhile, in situ CSI-MS and 1H-NMR spectra recognized
several guanidinium cuprates ion-pairs and copper-alkynide
complex which is a complementary to the current Cu-catalyzed
asymmetric allylic alkylation mechanistic study.
Biography
Xi-Yang Cui is working as a assistant professor at Nanyang Technological University
at Singapore .He belongs to chemistry department
xcui003@e.ntu.edu.sgXi-Yang Cui et al., J Biotech and Phyto 2017