Pauson RhCl

Transition metal complexes other than Co2(CO)8 catalyse the Pauson Khand reaction. The complex [RhCl(CO)2]2 catalyses the reaction of 224 [97], and Ru3(CO)12 [98] also catalyses these reactions at somewhat high temperatures. Highly enantioselective cyclization of 225 is catalysed by the chiral Ti(ebthi) complex to give 226 with 94% ee [99]. 

A Pauson-Khand type reaction of enynes, where the CO source is an aldehyde, has been reported by Morimoto and coworkers. This CO-transfer carbonylation system was carried ont with monomeric or dimeric rhodium complexes supported by monodentate or chelating phosphine ligands (e g. [RhCl(cod)]2/dppe or dppp [RhCl(CO)PPh3]). This reaction is snccessfiil for a series of enynes and aldehydes (Scheme 28). 

The [(cod)RhCl]2 complex can be used as a catalyst forthe Pauson- Khand reaction under CO. The true catalyst may be formed by exchange of the two ligands (to CO and DPPP). ... 

Figure 4 Catalytic Pauson-Khand reaction of an enyne in the presence of formaldehyde in wate as described by Fuji et al. Conditions enyne (0.25 mmol), formaldehyde (5 equivalents), [RhCl(cod)]2 (5mol%), dppp/TPPS (10mol%/10mol%), SDS (2 equivalents), H2O (1.9 mL), 100 °C, N2. cod, cyclooctadiene dppp, l,3-bis(diphenylphosphanyl)propane SDS, sodium dode-cylsulfate TPPTS, triphenylphosphane-3,3, 3"-trisulfonic acid trisodium salt.

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