The complexes trans-PdCl2[eta(1)-P-(Ph2P)CH(Ph)CH(Me)CH(OMe)(2)](2) (1) and M(H)Cl[eta(2)-P,OH-(Ph2P)CH(Ph)CH(Me)CH(OH)OMe] [eta(2)-P, C(O)-(Ph2P)CH(Ph)CH(Me)C(O)], M = Rh (3) and Ir (4), are synthesized by reacting the phosphinoaldehyde [3-(diphenylphosphino)-3-phenyl-2-methyl]propionaldehyde [(Ph2P)(2)CH(Ph)CH(Me)CHO] with trans-PdCl2(PhCN)(2), [RhCl(COD)](2), and [IrCl(COD)](2), respectively, in MeOH; trans-PdCl2[eta(1)-P-(Ph2P)CH(Ph)-CH(Me)CHO](2) (2) is isolated from the same reaction in CH2Cl2. One diastereomer of each of the complexes 1, 3 center dot MeOH, and 4 center dot MeOH was characterized by X-ray analysis. The stereochemistry of such complexes in the solid state and in solution (MeOH and CH2Cl2) is discussed. In CD2Cl2, NMR data suggest that the coordinated hemiacetal moiety of 3 (but not 4) undergoes reversible loss of MeOH; this process is associated with equilibria between various diastereomers of 3 that were investigated by P-31{H-1}, C-13{H-1}, H-1, H-1{P-31}, and HSQC and HMBC H-1/P-31{H-1} and H-1/C-13{H-1} NMR spectroscopies. Complexes 3 and 4 reveal a new chelate bonding mode via a P atom and the hydroxyl 0 atom of a hemiacetal. Solvent-dependent stereochemical changes within solution species imply that such chiral phosphinoaldehydes are not likely to be useful ligands for applications in asymmetric catalysis, although conditions are suggested for testing the complexes as potential precursors for nonasymmetric catalytic processes.