Highly Chemoselective Metal-Free Reduction of Phosphine Oxides to Phosphines
摘要:
Unprecedented chemoselective reductions of phosphine oxides to phosphines proceed smoothly in the presence of catalytic amounts of specific Bronsted acids. By utilizing inexpensive silanes, e.g., PMHS or (EtO)(2)MeSiH, other reducible functional groups such as ketones, aldehydes, olefins, nitriles, and esters are well-tolerated under optimized conditions.
Novel catalytic reductions of tertiary and secondaryphosphineoxides to phosphines have been developed. Using tetramethyldisiloxane (TMDS) as a mild reducing agent in the presence of copper complexes, PO bonds are selectively reduced in the presence of other reducible functional groups (FGs) such as ketones, esters, and olefins. Based on this transformation, an efficient one pot reduction/phosphination