PHIP Studies of Stereoselective Reactions

PHIP allows also the PASADENA investigation ofthe stereoselectivity ofa reaction. A typical example is given in Ref [70], where the stereoselective hydrogenation of 3-hex-yne-l-ol under the influence of the cationic ruthenium complex [Cp Ru(// - 

CH3CH=CHCH=CHC00H)][CF3S03] is shown in a iH-PHIP experiment (see Fig. 21.10). The spectrum reveals the characteristic PFIIP polarization pattern of adsorptive and emissive lines. This polarization pattern proves the pair-wise transfer of the para-hydrogen to the substrate. The observed anti-phase coupling constant of 

5 Hz is a typical value for an olefinic trans coupling constant and identifies the formation of the corresponding (i )-alkene by trans-hydrogenation of the substrate. 

---