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Amide-directed hydrocarbonylation of 3-butenamide(1) catalyzed by rhodium complexes such as RhCl(PPh 3 ) 3 , RhCl(CO)(PPh 3 ) 2 , HRh(CO)(PPh 3 ) 3 , and Rh 4 (CO) 12 gives a mixture of 3,4-dihydro-2-pyridone (2), 4-methyl-3-pyrrolin-2-one (3), and a unique heterodimer, 6-(4-methyl-2-oxo-3-pyrrolin-1-yl)-2-piperidone (4)

Rhodium-catalyzed silylformylation and amidocarbonylation are applied to the syntheses of pyrrolizidine alkaloids, (±)-isoretronecanol and (±)-trachelanthamidine, from 5-ethynyl-2-pyrrolidinone.

Reactions of hydrosilanes with 1-hexyne catalyzed by Co 2 Rh 2 (CO) 12 , Rh 4 (CO) 12 , ( t BuNC) 4 RhCo(CO) 4 , and Rh(acac)(CO) 2 at 25°C and atmospheric pressure to 10 atm of carbon monoxide give (Z)-1-silyl-2-formyl-1-hexenes ( 1 ), which are the products of “silylformylation”, and/or ( E )-1-silyl-1-hexenes ( 2 ). The ratio of silylformylation vs. hydrosilylation products depends on the electronic nature of hydrosilane used, e.g., PhMe 2 SiH gives 1 almost exclusively whereas (MeO) 3 SiH favors the formation of 2 . When trialkylsilanes such as Et 3 SiH and EtMe 2 SiH are used, the reaction catalyzed by Co 2 Rh 2 (CO) 12 or ( t BuNC) 4 RhCo(CO) 4 gives 2,5-bis(n-butyl)-3-silylcyclopent-2-en-1-one ( 3 ) as a major product, which is a unique silylcarbocyclization product. Mechanism of the formation of 3 is discussed on the basis of deuterium-labeling experiments. Chemoselective silylformylations of alkenynes, a dialkyne, and an alkynyl nitrile proceed in high yields in which alkene and nitrile functionalities are inert for the reaction. Silylformylation is successfully applied to the syntheses of pyrrolizidine alkaloids, (±)-isoretronecanol and (±)-trachelanthamidine, from 5-ethynyl-2-pyrrolidinone ( 6 ) in combination with amidocarbonylation.

Intramolecular amidocarbonylation of 3-butenamide catalyzed by a rhodium complex with excess PPh 3 gives 3,4-dihydro-2-pyridone selectively, whereas the same reaction using P(OPh) 3 affords a unique heterodimer in excellent yield. The reaction of 4-pentenamide gives 4-methyl-3,4-dihydro-2-pyridone exclusively regardless of the structure of rhodium catalysts.