Na-D15, a sodium dispersion reagent with sodium particle size of 5-15 μm, is a nonpyrophoric reagent that can be handled in air. A broad range of aliphatic ester substrates were reduced to primary alcohols by Na-D15/i-PrOH with good yields. The method compares favorably with modern metal hydride reductions and is much safer and efficient than the traditional Bouveault-Blanc reduction.
J. An, D. N. Work, C. Kenyon, D. J. Procter, J. Org. Chem., 2014, 79, 6743-6747.
Sodium in silica gel (Na-SG) - a safe, free-flowing powder - has been used for the Bouveault-Blanc reduction of various aliphatic esters. Primary alcohols were prepared in excellent yield under mild reaction conditions.
B. S. Bodnar, P. F. Vogt, J. Org. Chem., 2009, 74, 2598-2600.
A practical and scalable single electron transfer reduction enables the reduction and reductive deuteration of tertiary amides in the presence of sodium dispersions. The chemoselectivity of this method highly depends on the nature of the proton donor. Whereas the combination of Na/EtOH affords alcohol products, the use of Na/NaOH/H2O leads to the formation of amines.
B. Zhang, H. Li, Y. Ding, Y. Yan, J. An, J. Org. Chem., 2018, 83, 6006-6014.
A practical and cost-efficient reductive deuteration of nitriles under single-electron transfer conditions enables the synthesis of α,α-dideuterio amines in excellent yields using bench stable and commercially available sodium dispersions and EtOD-d1.
Y. Ding, S. Luo, A. Adijiang, H. Zhao, J. An, J. Org. Chem., 2018, 83, 12269-122274.
Reduction of stilbenes with Na metal in dry THF allowed easy access to various 1,2-diaryl-1,2-disodiumethanes. These diorganometallic intermediates gave 1,2-diarylethanes upon aqueous work up, or trans-1,2-diaryl-substituted cyclopentanes by cycloalkylation with 1,3-dichloropropanes.
U. Azzena, G. Dettori, C. Lubinu, A. Mannu, L. Pisano, Tetrahedron, 2005, 61, 8663-8668.
The use of bench-stable sodium dispersions and recoverable 15-crown-5 ether enables a significantly improved, practical, and chemoselective ammonia-free Birch reduction of a broad range of aromatic and heteroaromatic compounds in excellent yields.
P. Lei, Y. Ding, X. Zhang, A. Adijiang, H. Li, Y. Ling, J. An, Org. Lett., 2018, 20, 3439-3442.
The use of sodium in silica gel enables an efficient synthesis of symmetrical disulfanes from organic thiocyanates at room temperature. This protocol provides an attractive alternative to existing methods for the preparation of symmetrical disulfanes as it avoids the use of foul-smelling thiols.
C. K. Maurya, A. Mazumder, A. Kumar, P. K. Gupta, Synlett, 2016, 27, 409-411.