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Iridium(I) Catalysts, Bipyridine Ligands, and
Borylation Reagents from Aldrich:
Ir(I) Catalysts Bipyridine Ligands Borylation Reagents
For a complete list of C–H borylation reagents available from Aldrich
Chemistry, please visit Aldrich.com/borylation
Carboranes as Superweak Anions
The chemistry of weakly coordinating anions, or superweak anions,
continues to be actively investigated within many laboratories for a
variety of purposes. These useful molecules often allow for the isolation
of extremely reactive salts of cations, making them applicable to the ever
growing list of chemical tasks that require highly reactive cations. These
uses include the catalytic polymerization of olefi ns, the catalytic formation
of C–C bonds, the manufacture of high-current-density lithium batteries,
and the activation of C–H bonds. Discover how carboranes from Aldrich
can advance your research.
Carboranes from Aldrich:
F
B F
B
B
F
Cl
Ir Ir
Cl
683094
CH3
O
Ir Ir
O
B
CH3
685062
[Ir(COE) 2 Cl] 2
377155
Ir
685011
F
B
B
F
F F F
B
B
F
F B
F
B Cs
B
Cs
B
F
N N
36759 473294
H3C CH3
N N
569593
H3C CH3
N N
513040
H3CO OCH3
N N
536040
t-Bu t-Bu
N N
515477
F
F
B
B
F
B
B
F
B
B
F
B
B
F
F
B
B
F F F
723509 720887
H3C
H3C
H3C
H3C H3C
H3C
H
H
B
B
O O
B B
O O
O
B
O
CH3
CH3
CH3
CH3
655856
O O
B B
O O
473286
O
B
O
188913
O
B
O
518808
F
F
Ready to scale up? For competitive quotes on larger quantities or custom synthesis, contact your local Sigma-Aldrich offi ce, or visit safcglobal.com.
K
K
CH3
CH3
CH3
CH3 O CH3
B
O CH3
Frustrated Lewis Pairs as Hydrogenation
Catalysts
Catalysis
The hydrogenation of organic substrates with molecular hydrogen (H2)
has been used for purposes ranging from the large-scale upgrading of
crude-oil, to the synthesis of fi ne chemicals used in food, agriculture, and
the pharmaceutical industry. While the majority of methods rely on the
use of costly precious metal catalysts, recent work from the lab of Professor
Douglas W. Stephan has illustrated the use of frustrated Lewis pairs
for the same purpose. 1,2 These powerful non-metallic catalysts contain
both Lewis acidic (borane) and Lewis basic (phosphine) moieties that
cannot be quenched internally due to steric constraints. Because of this
unquenched reactivity, these organic catalysts are used to activate a variety
of small molecules, including the heterolytic cleavage of H2, leading to
a powerful catalyst system for the hydrogenation of imines and aziridines
(Scheme 3).
Scheme 3: Frustrated Lewis pairs for the hydrogenation of imines
and aziridines.
Reference: (1) Welch, G. C.; San Juan, R. R.; Masuda, J. D.; Stephan, D. W. Science 2006, 314,
1124. (2) (a) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew. Chem., Int. Ed. 2007,
46, 8050. (b) Chase, P. A.; Welch, G. C.; Jurca, T.; Stephan, D. W. Angew. Chem., Int. Ed. 2007,
46, 9136.
Frustrated Lewis Pairs from Aldrich:
F
F
t-Bu
N
703087 5 mol %
t-Bu
NH
H Ph
5 atm H 2
H Ph
H
98 %
F
F
F F
H
B
F F
F F
F
Ph
F
Ph
N
Ph
F
t-Bu
P
t-Bu
F
H +
703095
5 atm H 2
F
F
For a complete list of Frustrated Lewis pairs available from Aldrich
Chemistry, please visit Aldrich.com/fl p
F
F
F
F
10 mol %
F
BH
F F
F
F
F
F
H3C Ph
NH
H +
F H3C 703087 703095
Ph
Ph
98 %
P
CH 3
CH3 CH3
CH3
9