Cobalt (I)??Catalyzed Asymmetric [2+ 2+ 2] Cycloaddition of Alkynes and Nitriles: Synthesis of Enantiomerically Enriched Atropoisomers of 2??Arylpyridines
The [2+ 2+ 2] cycloaddition of alkynes and nitriles is a useful tool in organic synthesis, allowing easy access to a broad variety of benzene and pyridine derivatives in one step. Although achiral reactions of this type are well documented,[1] there are only two examples of catalytic asymmetric [2+ 2+ 2] homocyclizations yielding benzene derivatives with simultaneous introduction of an element of chirality.[2, 3]
