Palhdiam-catalyzed diastereo-dfierentiative tandem connection of cis-akenyl iodide. cyclic fragment, and terminal acetylene was executed. The discrimination of the diastereotopic face and olefinic carbons of norbotnene was achieved with accompanying isomerization of the cis-geometry of the olefii IO tram in good yields.
When a bifunctional molecule has an internal mirror, the two halves are enantiotopic. Differentiation of the each side of the plane is a current topic of a number of transformations in which achiral bifunctional compounds are converted into chiral products.1
Our previous investigations2 suggest that diastereodifferentiative tandem introduction of two side chains onto norbomene (1) is feasible as illustrated below. As the preceding report3 demonstrated, such a stereocontrolled bond formation leads to the creation of four chiralities by breaking the o-symmetry of 1. Although various nonselective assembly with 1 have been reported,4 the previous catalytic processes require a tedious workup. We found that the envisaged tandem assembly smoothly proceeds by the employment of copper(I) iodide as a co-catalyst, known as a usual catalyst system for the coupling of acetylene and vinyl halide.