Tandem catalysis: the sequential mediation of olefin metathesis, hydrogenation, and hydrogen transfer with single-component Ru complexes.

General information. All manipulations were performed in a N2 filled drybox or using standard Schlenk techniques. Allyl benzene, methyl vinyl ketone, pchlorostyrene, methyl methacrylate, diethyl diallylmalonate (3), and 1,6-heptadien-4ol (6) were purchased from Aldrich and used without further purification. cis-4Cyclopentene-1,3-diol and (+)-citronellal were purchased from Fluka and used without further purification. cis-2-Butene-1,4-diol diacetate and 5-acetoxy-1-hexene were purchased from TCI America and used without further purification. Complexes (PCy3)2Cl2Ru=CHPh (1) and (H2IMes)(PCy3)Cl2Ru=CHPh (2) and substrates 1,6heptadien-4-one (6), 1,8-nonadien-5-one (12), 2-allyl-2-(2-methyl-allyl)-malonic acid diethyl ester (15), 1,4-bis-allyloxy-but-2-yne (21), 2-methyl-acrylic acid but-3enyl ester (24), N-allyl-N-isopropyl-acrylamide (27), and undec-10-enoic acid but-3enyl ester (30) were prepared as previously reported. Substrates 4,4dicarbethoxycyclopentene (4), cyclopent-3-enone (7), cyclopent-3-enol (10), cyclohept-4-enone (13), 4,4-dicarbethoxy-1-methylcyclopentene (16), 2,5,2',5'tetrahydro-[3,3']bifuranyl (22), 3-methyl-5,6-dihydro-pyran-2-one (25), 1-isopropyl1,5-dihydro-pyrrol-2-one (28), oxacyclotetradec-11-en-2-one (31), acetic acid 4phenyl-but-2-enyl ester (33), acetic acid 7-oxo-oct-5-enyl ester (35), 4-phenyl-but3-en-2-one (37), and 3-(4-chloro-phenyl)-acrylic acid methyl ester (39) are known metathesis products. H (300 MHz) and C NMR (75 MHz) spectra were recorded on a GE-300 NMR, referenced to residual protiated solvent (resonances downfield to the standard are reported as positive), and are reported in parts per million (ppm).