Reduction

Reduction is a chemical reaction in which the target substances receive electrons, and is one of the most fundamental reactions in organic chemistry including the deoxygenation reaction and the hydrogenation reaction. The well-known reducing agents include LiAlH41), boranes used in the hydride reduction, and hydrazine used in the Wolff-Kishner reduction.2) In recent years, the radical reductive reaction using silane compounds tris(trimethylsilyl)silane3) and tetraphenyldisilane (TPDS)4) as radical reducing agents has been developed avoiding the use of highly toxic tin compounds. This section shows the typical reducing agents.

C1614 C1614 C1615 C1615 C2023 C2023
T1896 T1896 T1437 T1437 B1827 B1827
B1139 B1139 B3018 B3018 M0898 M0898
B1569 B1569 B1264 B1264 T2346 T2346
C1492 C1492 C0778 C0778 D2403 D2403
D3761 D3761 D1843 D1843 D1842 D1842
D2196 D2196 D1825 D1825 D2406 D2406
D2820 D2820 H0172 H0172 H0204 H0204
H0169 H0169 H0170 H0170 H0173 H0173
H0174 H0174 L0170 L0170 L0203 L0203
L0186 L0186 L0159 L0159 D2581 D2581
P1291 P1291 P1681 P1681 P1380 P1380
S0467 S0467 S0480 S0480 S0396 S0396
S0481 S0481 S0394 S0394 T0917 T0917
T0852 T0852 T1553 T1553 T1572 T1572
T0398 T0398 T1180 T1180 T0662 T0662
T1334 T1334 T1533 T1533 T1181 T1181
T1819 T1819 T0661 T0661 Z0010 Z0010
C1614 (+)-B-Chlorodiisopinocampheylborane (58% in Hexane, ca. 1.6mol/L)
C1615 (-)-B-Chlorodiisopinocampheylborane (60% in Hexane, ca. 1.7mol/L)
C2023 (-)-B-Chlorodiisopinocampheylborane (60% in Heptane, ca. 1.7mol/L)
T1896 1,1,2,2-Tetraphenyldisilane
T1437 1,1,3,3-Tetramethyldisiloxane
B1827 1,2-Bis(tert-butylthio)ethane Borane
B1139 Bis(triphenylphosphine)copper Tetrahydroborate
B3018 Borane - 2-Picoline Complex
M0898 Borane - Morpholine Complex
B1569 Borane - Pyridine Complex
B1264 Borane - tert-Butylamine Complex
T2346 Borane - Tetrahydrofuran Complex (8.5% in Tetrahydrofuran, ca. 0.9mol/L) (stabilized with Sodium Borohydride)
C1492 Chlorodiisopropylsilane
C0778 Chlorodimethylsilane
D2403 Diethoxymethylsilane [Hydrosilylating Reagent]
D3761 Diethylsilane
D1843 Dimethyl Sulfide Borane
D1842 Dimethylamine Borane
D2196 Dimethylphenylsilane
D1825 Diphenylmethylsilane
D2406 Diphenylsilane
D2820 Diphenylsilane
H0172 Hydrazine Monohydrate
H0204 Hydrazine Monohydrate (79%)
H0169 Hydrazine Dihydrobromide
H0170 Hydrazine Dihydrochloride
H0173 Hydrazine Monohydrobromide
H0174 Hydrazine Monohydrochloride
L0170 Lithium Aluminum Hydride (10% in Tetrahydrofuran, ca. 2.5mol/L)
L0203 Lithium Aluminum Hydride (Powder)
L0186 Lithium Borohydride (ca. 3mol/L in Tetrahydrofuran)
L0159 Lithium Tri-tert-butoxyaluminum Hydride (20% in Tetrahydrofuran, ca. 0.7mol/L)
D2581 N,N-Diethylaniline Borane
P1291 Phenylsilane
P1681 Potassium Borohydride
P1380 Potassium Tri-sec-butylborohydride (ca. 1.0mol/L in Tetrahydrofuran)
S0467 Sodium Bis(2-methoxyethoxy)aluminum Dihydride (70% in Toluene, ca. 3.6mol/L)
S0480 Sodium Borohydride
S0396 Sodium Cyanoborohydride [Reducing Agent]
S0481 Sodium Hydride (60%, dispersion in Paraffin Liquid)
S0394 Sodium Triacetoxyborohydride
T0917 Tetrabutylammonium Borohydride [Reducing Reagent]
T0852 Tetramethylammonium Borohydride [Reducing Reagent]
T1553 Tetramethylammonium Triacetoxyborohydride
T1572 Tri-n-octyltin Hydride [Reducing Reagent]
T0398 Trichlorosilane
T1180 Triethylamine Borane
T0662 Triethylsilane
T1334 Trihexylsilane
T1533 Triisopropylsilane
T1181 Trimethylamine Borane
T1819 Triphenylphosphine Selenide
T0661 Triphenylsilane
Z0010 Zirconocene Chloride Hydride

Many reducing agents may spontaneously ignite on contact with air, or may react violently with water to produce flammable gases. Sufficient safety measures, such as using safety shields, wearing protective equipment, and using extreme caution should be taken when working with these reagents as well as disposing of the reagents.

Literature

1) J. Malek, M. Cerny, Synthesis, 1972, 217 (Review) [DOI].
2) N. J. Kishner, J. Russ. Phys. Chem. Soc., 1911, 43, 582; L. Wolff, Ann., 1912, 394, 86 [DOI]; R. O. Hutchins, M. K. Hutchins, Comprehensive Organic Synthesis, 1991, 8, 327 (Review).
3) C. Chatgilialoglu, D. Griller, M. Lesage, J. Org. Chem., 1988, 53, 3641 [DOI].
4) O. Yamazaki, H. Togo., S. Matsubayashi. M. Yokoyama, Tetrahedron Lett., 1998, 39, 1921 [DOI].


kdjoad0000003vxj