Stereoselective Preparation of Distant Stereocenters (1,5) within Acyclic Molecules

The development of a modular and diastereodivergent approach to acyclic products bearing two distant stereocenters in a 1,5 relationship is reported. Remarkably, it was accomplished in just three catalytic steps from commercially available alkynes. This sequence generates the desired distant stereocenters efficiently and with high diastereocontrol and a perfect E:Z ratio. The approach was used for a noniterative formal synthesis of the alpha-tocopherol side chain.