-
Visible Light
Photoredox
Catalysis
Literature Meeting
Christopher K. Haley
March 7, 2014
Noyes 147
-
N
N
Br
H
NH
O
Boc
Cbz
Me
Utilizing the Radical IntermediateTotal Synthesis of
(+)-Gliocladin C
N
N
H
NH
O
Boc
Cbz
Me
Ru(bpy)3Cl (1.0 mol %)
NBu3, DMF visible light
NH
CHO
HN
CHO
N
N
H
NH
O
Boc
Cbz
Me
HN
Ru(PPh3)3Cl (1.0 equiv)
xylenes, 140 °C
NH
N
H
HN
(+)-gliocladin C
N
O
Me
O
O
Stephenson, C. R. Angew. Chem., Int. Ed. 2011, 50, 9655.
-
4–8 mol % RuL3
collidine, MeCN, visible light
RuL32+
*RuL32+ RuL3
3+
hu
Photocatalyzed Oxidation
Cano-Yelo, H. Tetrahedron Lett. 1984, 25, 5517
O
Ph
N2
O
Ph
–N2
OH
H
OH OH O
H
O
Ph
N
N
CO2i-Pr
CO2i-Pr
RuII
3
OH O
HR R
-
RuII
N
N
N
N
N
N
Ru(bpy)32+
Enantiomeric Ru(bpy)2+
RuII
N
N
N
N
N
N
Ru(bpy)32+
D L
N
N
R
R
RuII
3
O
O
R=
OH
X
D-Ru(menbpy)32+
Co(acac)3 (1.2 equiv)
MeCN, visible light
X
OH
OH
X
X= H, 16% ee
Ohkudo, K. J. Chem. Soc., Chem Commun. 1993, 909.
X= OMe, 4% ee
-
Ru(bpy)2+*Ru(bpy)32+
Ru(bpy)3+
hu
Amine Oxidationa-Amino Radicals
NPh
NPh
NPh
Reiser, O. Org. Lett. 2012, 14 , 672
–H+
NPh
MeO
NPh
MeO
MVK
58% yield (Ru)68% yield (Ir)
-
Ir(ppy)3
*Ir(ppy)3 Ir(ppy)3+
hu
Amine Oxidationa-Amino Radicals
MacMillan, D. W. J. Am. Chem. Soc. 2014, 136 , 626.
NC
CN
NC
CN
–CN
82% yield
ArNC
Ar = Electron Poor Aryl
Ir(ppy)3 (1.0 mol %), K2HPO4
octanal, DMA23 °C, 12–24 h
visible light
28 examples51–82% yield
R SH
–H•
OMe
OMeOMe
CN
NC
OMe
NC
Ar
OPG
Ar
OPG
Ar
MeO
O
SH
R S•
-
Diels–Alder Cycloaddition
HN
O
MeMe
O
O
O
O
Me
Me
O
NH
Me Me
O
O
O
NH
Me Me
Me
Me
heitziamide A
Me
Me
150 °C
72 h
60% yield
Incorrect Regioselectivity
Yoon, T. P. J. Am. Chem. Soc 2011, 133, 19350.
-
Summary
-Visible light photoredox catalysts can be easily tuned
-Catalysts can act as either a reductant or oxidant, causing net
oxidative, reductive or
neutral reactions.
-Photoredox catalysis provides a mild way of affecting a wide
variety of reacions.
