Modular Mo-based catalysts for efficient asymmetric olefin metathesis. Catalytic enantioselective synthesis of cyclic ethers and acetals

Chiral Mo-based complexes 1–3 promote the catalytic enantioselective ring-closing metathesis of various polyenes to afford unsaturated furans, pyrans and siloxanes efficiently and in high ee (70–98% ee). The structural modularity of this class of chiral catalysts plays a critical role in these studies. Modification of the diolate or imido moities of these chiral catalysts gives rise to a range of complexes that can be screened for higher reactivity and/or enantioselectivity.