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 metal hydrides such as LiAlH41), boranes used in the hydride reduction, and hydrazine used in the Wolff-Kishner reduction.2) Sodium tris(1,1,1,3,3,3-hexafluoroisopropoxy)borohydride (1) is a selective reducing agent developed by Toshima et al. Aldehydes are selectively reduced in the presence of ketones and other reducible functions using 1 to afford the corresponding primary alcohols in high yields.3)
In addition, the radical reductive reaction using silane compounds tris(trimethylsilyl)silane4) and tetraphenyldisilane (TPDS)5) as radical reducing agents has been developed avoiding the use of highly toxic tin compounds. This section shows the typical reducing agents.
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.