Cross Dehydrogenative Coupling Reactions by Ball Milling - Ball Milling Towards Green Synthesis: Applications, Projects, Challenges - page 102

Table 5.2 CDC reaction of tetrahydroisoquinolines with alkynes by ball milling. a

R 1

N

R 2 Ar

DDQ

R 1

copper ball

+

H R

N

Silica gel

R 2 Ar

ball milling

1 6 7

1a : R 1 = R 2 = H, Ar = Ph
1b : R 1 = R 2 = H, Ar = 4-MeOC 6 H 4
1c : R 1 = R 2 = H, Ar = 4-MeC 6 H 4
1d : R 1 = R 2 = OMe, Ar = Ph
1e : R 1 = R 2 = OMe, Ar = 4-MeC 6 H 4

6a : R = Ph
6b : R = 4-MeC 6 H 4
6c : R = 4-FC 6 H 4
6d : R = 2-Py
6e : R = Pr
6f : R = CO 2 Me

N

N

N N

N

F

7a 7b 7c 7d

78%, 20 min 74%, 20 min 87%, 20min 69%, 40 min

N

N

N

N

OMe

OMe

O OMe

7e 7f 7g 7h

67%, 30 min 73%, 30 min 75%, 30 min 70%, 30 min

MeO

N

N

N N MeO

OMe

OMe

O e

F

7i 7j 7k 7l

84%, 20 min 72%, 30 min 79%, 20 min 75%, 40 min