Abstract
Application of ultrafine metal particles, 10-1000 Å in diameter, to organic syntheses are reviewed as reagents and catalysts. Ultrafine magnesium particles are effectively reactive to organic compounds with rather poor reactivities such as fluorobenzenes and bromobenzenes, yielding the Grignard reagents. Ultrafine zinc particles also react with less reactive bromobenzenes under mild conditions. Ultrafine particles of palladium, platinum, rhodium, ruthenium, copper, and others show high catalytic activity and selectivity in various organic syntheses. The selective catalytic reactions involve
1) hydrogenation of C-C double bonds, nitro groups, and aromatic rings, 2) hydrogenation of dienes to the corresponding monoenes, 3) hydrogenolysis of cystine to cysteine, 4) hydration of acrylonitrile to acrylamide, and 5) hydration of C-C double bond, followed by dehydrogenation of the resulting alcohol. The features of ultrafine metal particles used in organic syntheses are discussed.
