44
numerous efforts have been devoted on the methodology development for introduction of CF 3 group into organic molecules. In 2010, Qing and co-workers demonstrated an elegant copper-mediated aerobic trifluoromethylation of terminal alkynes
(Scheme 3.4) [22]. This oxidative cross-coupling of terminal alkynes with CuCF 3
(generated in situ from Me 3 SiCF 3 , KF, and CuI) provides a straightforward, and
practically useful way for the preparation of trifluoromethylated acetylenes, which
are versatile building blocks in many pharmaceuticals.
R
1
H
R
1
R
2
[Pd] or [Cu] or [Ni]
(HO) 2 B R
2
Scheme 3.3 Oxidative coupling between terminal alkynes and boronic acids
R
H
TMS CF 3
R
CF 3
CuI / 1,10-Phen
KF, DMF
100 °C, air
CF 3
74%
CF 3
65%
MeO
CF 3
80%
CF 3
84%
CF 3
72%
CF 3
71%
CF 3
84%
CF 3
78%
CF 3
76%
N
S
F
MeO
Ph
N
Me
Ph
CF 3
86%
CF 3
79%
CF 3
71%
Br
Me
Me
Me
Cl
EtO 2 C
Scheme 3.4 Copper-mediated aerobic trifluoromethylation of terminal alkynes
C. He