Diphenylsilane
Recent Literature
Activation of diphenylsilane in the presence of a catalytic amount of an
N-heterocyclic carbene (NHC) enables hydrosilylation of carbonyl derivatives
under mild conditions. Presumably, a hypervalent silicon intermediate featuring
strong Lewis acid character allows dual activation of both the carbonyl moiety
and the hydride at the silicon center. Some interesting selectivities have been
encountered.
Q. Zhao, D. P. Curran, M. Malacria, L. Fensterbank, J.-P. Goddard, E. Lacôte, Synlett, 2012, 23,
433-437.
The [RuCl2(p-cymene)]2/Ph2SiH2
catalytic system is very efficient for the reductive amination of aldehydes with
anilines to provide secondary amines and tertiary amines in good yields. The
method is highly chemoselective and tolerates a wide range of functional groups,
such as NO2, CN, CO2Me, F, Cl, Br, OMe, Me, furyl and
alkyl.
B. Li, J. Zheng, W. Zeng, Y. Li, L. Chen, Synthesis, 2017,
49, 1349-1355.
An environmentally benign, tin-free radical "on water" addition of alkyl iodides
to the C=N bond of hydrazones in the presence of diphenylsilane and
triethylborane afforded the corresponding addition products in good yields. The
developed protocol can be applied to the synthesis of 3-substituted
isoindolinone derivatives.
T. K. Nam, D. O. Jang, J. Org. Chem., 2018, 83,
7373-7379.
An organophosphorus-catalyzed C-N bond-forming reductive coupling of
nitroalkanes with arylboronic acids and esters shows excellent chemoselectivity
for the nitro/boronic acid substrate pair, allowing the synthesis of
N-(hetero)arylamines rich in functionalization.
G. Li, Y. Kanda, S. Y. Hong, A. T. Radosevich, J. Am. Chem. Soc.,
2022, 144, 8242-8248.
The combination of Co(OAc)2 with a chiral
phosphine-amido-oxazoline (PAO) ligand catalyzes a mild and efficient asymmetric
hydrosilylation of α-oxygenated ketones to provide synthetically useful 1,2-diol
derivatives. The optically enriched products can be converted into chiral
α-hydroxy acids, 1,3-dioxolan-2-ones, ethylene oxides, and 1,2,3-1H-triazoles.
H. Wen, Y. Chen, L. Shi, J. Chen, Y. Luo, Y. Xia, Org. Lett., 2023, 25,
2184-2189.
A mild, enantioselective hydrosilylation of 3-oxo-3-arylpropionic acid
methyl or ethyl esters using axially chiral BINAM N-heterocyclic carbene (NHC)-Rh(III) complexes
as catalysts gave 3-hydroxy-3-arylpropionic acid
methyl or ethyl esters in good yields with good to excellent
enantioselectivities under mild conditions.
Q. Xu, X. Gu, S. Liu, Q. Duo, M. Shi, J. Org. Chem., 2007,
72, 2240-2242.
The combination of an air-stable Ni precatalyst, dimethyl dicarbonate as an
activator, and diphenylsilane as reductant enables a direct conversion of
carboxylic acids to aldehydes for a wide range of substrates in good yields and
with no overreduction to alcohols.
A. V. Iosub, S. Moravčík, C.-K. Wallentin, J. Berman,
Org. Lett., 2019, 21, 7804-7808.
3-Methyl-1-phenylphospholane-1-oxide as precatalyst and an organosilane reducing
agent are the key components in a Wittig reaction catalytic in phosphine.
Various heteroaryl, aryl, and alkyl adehydes could be efficiently converted to
the corresponding alkenes in good yield using this precatalyst. The protocol
also functions well on larger scale.
C. J. O'Brien, J. L. Tellez, Z. S. Nixon, L. J. Kang, A. L. Carter, S. R. Kunkel,
K. C. Przeworski, G. A. Chass, Angew. Chem. Int. Ed., 2008, 48,
6836-6839.
Cu-catalyzed asymmetric conjugate reduction of
β-substituted ketones leads to enantiomerically enriched
diphenylsilyl enol ethers, which are utilized in a diastereoselective Pd-catalyzed
α-arylation of various aryl bromides to yield disubstituted cycloalkanones with
excellent levels of enantiomeric and diastereomeric purity. The procedure can be
carried out in one-pot.
J. Chae, J. Yun, S. L. Buchwald, Org. Lett., 2004, 6, 4809-4812.
A catalytic anti-Markovnikov hydrobromination of aryl- and alkyl-substituted
terminal alkynes affords terminal E-alkenyl bromides in high yield and
with excellent regio- and diastereoselectivity. The reaction conditions are
compatible with a wide range of functional groups, including esters, nitriles,
epoxides, aryl boronic esters, terminal alkenes, silyl ethers, aryl halides, and
alkyl halides.
M. R. Uehling, R. P. Rucker, G. Lalic, J. Am. Chem. Soc., 2014,
136, 8799-8803.
Cu(I) catalysis enables an efficient and facile construction of trisubstituted exocyclic alkenes
in good yields under mild conditions in the presence of B2pin2.
Tetrasubsituted borylated or iodinated alkenes can also be isolated depending on
the reaction conditions. A preliminary mechanistic study showed that the reaction undergoes a radical
process, where B2pin2 plays an indispensable role.
S. Zhou, F. Yuan, M. Guo, G. Wang, X. Tang, W. Zhao, Org. Lett.,
2018, 20, 6710-6714.
A small ring phosphacycle (phosphetane) catalyzes the synthesis of unsymmetrical
hydrazines by cross-selective intermolecular NN reductive coupling of
nitroarenes and anilines in the presence of a hydrosilane as the terminal
reductant. The reaction offers good chemoselectivity and functional group
tolerance.
G. Li, S. P. Miller, A. T. Radosevich, J. Am. Chem. Soc.,
2021, 143, 14464-14469.
