Consecutive hydroformylation-Wittig reaction

Consecutive hydroformylation-Witttig reaction is the last reported consecutive reaction involving hydroformylation. As in the case of 

The reaction is limited to stabilized ylides, because non stabUizided ylides are too basic and induce rhodium inactivation. 

Under hydroformylation conditions and in the presence of Ph3P=CHCOR, compound 189 leads to the oxo derivative 190. The process involves a sequence of reactions that includes initial hydroformylation to give the aldehyde 191 in a stereoselective way (see also Figme 26), Wittig olefination to give the trans conjugated alkene 192 and hydrogenation. 

Disubstituted ylides (i.e. PPh3=C(Me)COR) do not undergo hydrogenation and in consequence a,P-unsaturated ketones or esters are obtained. Ylides including the ester function provide low yields. The stereoselectivity of the process Is determined by the chelating (directing) group o-DPPB, and stereochemistries aU- syn, anti-syn, and all -anti can he obtained. 

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