14221-01-3

Reactions

Catalyst for Suzuki coupling of chiral secondary organoboronic esters. Palladium-catalyzed SNAr reactions for the synthesis of heteroaryl ethers. Catalyst for cross-coupling of a-diazocarbonyl compouns with arylboronic acids. Diastereoselective synthesis of trans-1,2-diazetidines. Palladium-catalyzed alkynyl iminium ion cyclization. Widely used reagent in a variety of transformations including Heck arylation, enyne and diyne cycloisomerization. Catalysts for cross-coupling.

Flammability and Explosibility

Nonflammable

Purification Methods

The palladium complex is recrystallised from EtOH. It should not be heated excessively as it dissociates to Pd(PPh3)3 and PdPh3 and then further to Pd(PPh3)2 and PPh3. It is also air sensitive as PPh3 is oxidized to PPh3O. It is stable only for short periods because on exposure to heat or air it turns from yellow to orange and dissociates in solution so the solutions should be used directly. However it can always be prepared freshly by mixing Pd(NO3)2 (2mmols) and PPh3(2mmols) in hot *C6H6 when vigorous evolution of nitric oxide occurs and a solid mass separates. This is collected and crystallised from EtOH. Its cryoscopic constant in *C6H6 (at 0.601g/20mL) corresponds to M 1156 [Malatesta & Angoletti J Chem Soc 1186 1957]. It is a useful catalyst for Suzuki coupling reactions [Trost Tetrahedron 33 2615 1977]. [Beilstein 16 IV 954.] This palladium catalyst bound to a polymer support (~0.06mmol/g) is also commercially available [cf Fenger & LeDrain Tetrahedron Lett 39 4287 1998]. [Beilstein 16 IV 954.]