[55123-60-0] · C42H35IP2Pd · Iodo(phenyl)bis(triphenylphosphine)palladium(II) · (MW 835.03)
Form Supplied in: prepared and used in situ.
Preparative Methods: formed from Pd(PPh3)
Handling, Storage, and Precautions: very reactive and unstable, therefore formed in situ. Decomposition results in palladium metal, which should be retained for recycling.
The title reagent is used to couple organic halides with carbanions stabilized by various metals. The organic halide initially oxidatively adds to the palladium catalyst, and so must be stable to b-elimination. This means that aryl and alkenyl halides are generally used. The general coupling reaction is shown in eq 1.
Organomercury reagents have been used with various groups including R1 = aryl, Me and R2 = aryl, acyl.3,4 The organometallic may also be a Reformatsky reagent5 or a Grignard reagent.6 Alkylstannanes7 have also been used.
Terminal alkynes are so acidic that they may be used directly without the need to form an organometallic (eq 2).8,9
Other palladium reagents can be used to effect the aforementioned coupling reactions and the transformation may be either stoichiometric or catalytic in palladium. Generally, the choice of a particular palladium reagent is a matter of experimentation. This is also the case for the carbonylation reactions below.
IPhPd(PPh3)2 catalyzes carbonylation of organometallics with Carbon Monoxide. This process is often accomplished in sequence with the aforementioned cross coupling. For example, ketones can be synthesized from organomercurials as shown in eq 3.10
Aryl halides can be carbonylated and the intermediate acyl organometallics coupled with other groups. For example, treatment of active methylene compounds with aryl halides and CO.11 When the reaction is carried out in the presence of alcohols or amines, esters or amides are formed.12 Cyanocarbonylation has also been reported (eq 4).13
IPhPd(PPh3)2 has also been used for the reduction of iminoyl chlorides to the corresponding Schiff bases.14 The germylation of organic halides has also been reported (eq 5).15
Ann K. Keep
Johnson Matthey, Royston, UK