Homogeneous hydrogenation catalyst: J. Chem. Soc.(A), 1711 (1966), useful e.g. for the selective reduction of an unhindered alkene, of an unconjugated in the presence of a conjugated alkene: Org. Synth. Coll., 6, 459 (1988), or an alkene in the presence of a nitro group: J. Org. Chem., 67, 3163 (2002). Hydroxyl groups protected as their allyl ethers may be deprotected by isomerization with Wilkinson's Catalyst to the more readily-hydrolyzed 1-propenyl ether: J. Org. Chem., 38, 3224 (1973). Aldehydes undergo decarbonylation with the complex: Tetrahedron Lett., 3969 (1965); J. Am. Chem. Soc., 93, 5465 (1971). The need for stoichiometric amounts of the complex, due to formation of an inactive Rh carbonyl complex, is a serious disadvantage. However, in the presence of Diphenyl-phosphonic azide, which regenerates the catalyst from the carbonyl complex, decarbonylations can be carried out catalytically at room temperature, providing a much more cost-effective and attractive method for this type of transformation: J. Org. Chem., 57, 5075 (1992). Catalyst for hydrosilylation reactions, e.g. with Triethyl-silane, including ɑ?-unsaturated ketones to silyl enol ethers, which can be hydrolyzed to saturated ketones: Organometallics, 1, 1390 (1982), and ɑ?-unsaturated esters to silyl ketene acetals with high (Z)-selectivity: Synth. Commun., 17, 1 (1989). Used by Grigg for the catalytic [2+2+2] cyclotrimerization of alkynes, providing an efficient route to benzene-fused ring systems. See, e.g.: J. Chem. Soc., Perkin 1, 1357 (1988). For an intermolecular example with reaction scheme, see 1,6-Heptadiyne. Intramolecular assembly of suitably constructed triynes can also be accomplished to form benzene rings: Tetrahedron, 45, 6239 (1989). Also catalyzes the [5+2] cycloaddition of vinylcyclopropanes and alkynes: J. Am. Chem. Soc., 117, 4720 (1995); 120, 1940 (1998). Co-catalyst giving improved results in intramolecular Heck coupling reactions catalyzed by Pd(OAc)2: J. Org. Chem., 64, 3461 (1999). Electron-deficient olefins undergo Rh-catalyzed 1,4-addition with Bis(pinacolato)-diboron, e.g. 2-cyclohexen-1-one to the ?-borylcyclohexanone: Tetrahedron Lett., 43, 2323 (2002).
