The Z-selective cross metathesis of allylic-substituted olefins is explored with recently developed ruthenium-based metathesis catalysts. The reaction proceeds with excellent stereoselectivity for the Z-isomer (typically> 95%) and yields of up to 88% for a variety of allylic substituents. This includes the first synthesis of Z-α, β-unsaturated acetals by cross metathesis and their elaboration to Z-α, β-unsaturated aldehydes. In addition, the reaction ...
