NaTure CHemiSTry
Articles
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O
Me
a
O
N
[Ru(bpy)3]Cl2
(0.5 mol%)
H
Me
t-Bu
HOTf
17
N
R'
.
H
O
CO2Et
CO2Et
20
Photoredox
catalyst
+
CO2Et
19a (20 mol%)
H
15 W CFL
R'
H
2,6-lutidine, DMF
Br
CO2Et
18a
Organic catalyst 19 (20 mol%)
b
O
O
Dithiocarbamate catalyst 1c (20 mol%)
R
R
+
H
Cl
2,6-lutidine (1.2 equiv.)
R'
R'
Blue LEDs, MeCN, 24 h, 25 °C
17
Br
CF3
F3C
Catalysts
CF3
N
SK
N
CF3
S
OTMS
H
Dithiocarbamate catalyst 1c
19b
19. Barton, D. H. R., George, M. V. & Tomoeda, M. 369. Photochemical
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Visible-light-mediated synthesis of amidyl radicals: transition-metal-free
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22. Giese, B. Formation of C–C bonds by addition of free radicals to alkenes.
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O
CO2Et
CO2Et
O
O
Ph
H
H
H
CN
butyl
butyl O
Ph
20: 77% yield, 74% e.e.
(using 19b)
21: 57% yield, 79% e.e.
(using 19b)
22: 60% yield, 90% e.e.
(using 19a)
Fig. 5 | Application in enantioselective radical catalysis. a, The catalytic
asymmetric α-alkylation of aldehydes using a visible-light-activated
ruthenium catalyst (Ru(bpy)32+). The chemistry uses alkyl bromide
derivatives36. b, Demonstration that the dithiocarbamate anion catalytic
strategy can extend the asymmetric alkylation of aldehydes to include alkyl
chlorides. Bpy: 2,2’-bipyridine; CFL: compact fluorescence lamp; SET:
single-electron transfer; TMS: trimethylsilyl.
Data availability:
The data supporting the findings of this study are available within the paper and
its Supplementary Information. Crystallographic data for Br-11, an analogue
of the major diastereoisomer of compound 11, have been deposited with the
Cambridge Crystallographic Data Centre, accession number CCDC 1839232.
Received: 9 August 2018; Accepted: 18 October 2018;
Published: xx xx xxxx
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