Triphenylphosphine → HCID 10571285, compound

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Reaction Steps

Pyridinone derivative (P) can also be derivatized to form pyridinone derivative (W) by the organometallic coupling of (trimethylsilyl)acetylene as shown in Reaction Scheme XIII. A similar result in Reaction Scheme XIII can be obtained for the corresponding derivative of pyridinone (E). wherein Z, R2, R3, and R4 are as defined in Reaction Scheme VI. Reagents for the organometallic coupling include PdCl2(PPh3)2 and Cul or other suitable organometallic reagents. The organometallic coupling is accomplished by combining the halogenated pyridinone derivative with (trimethylsilyl)acetylene and triphenylphosphine, PdCl2(PPh3)2 and Cul and then heating at 120 degrees Celcius for 72 hours. The preparation of pyridinone derivative (W) is illustrated by a procedure described by Padwa A., Sheehan S. M., and Straub C. S., J. Org. Chem. 1999, 64: 8648-8659 for an isomunchnone-based method for the synthesis of highly substituted 2(1H)-pyridones, the entirety of which is hereby incorporated by reference. The authors describe the palladium catalyzed coupling of (trimethylsilyl)acetylene with a triflate to provide a (trimethylsilyl)acetylene substituted compound. The specific preparation procedure employed by the authors involved the addition of Cul, followed by PdCl2(PPh3)2 to a solution containing triphenylphosphine in triethylamine. To this solution was added (trimethylsilyl)acetylene in toluene followed by the addition of trifluoromethanesulfonic acid 8-phenylsulfonyl-5-oxo-1,2,3,5-tetrahydroindolizin-6-yl ester. The mixture was heated at 115 degrees Celcius for 1 hour, cooled to room temperature, poured into ice water, extracted with CH2Cl2, washed with brine, and dried over Na2SO4. The organic extracts were filtered and concentrated under reduced pressure. The crude residue was subjected to flash silica gel chromatography to yield 8-phenylsulfonyl-6-trimethylsilanylethynyl-2,3-dihydro-1H-indolizin-5-one.

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