Stereoselective Additions of Chiral, Functionalized Organozinc Reagents to Achiral and Chiral Aldehydes: a Matched‐Mismatched Case in Organozinc Chemistry

The additions of the enantiomerically pure organozinc reagents 17 and 33 to the THF‐aldehyde 1 in the presence of the monodentate Lewis acid boron trifluoride—ether give the nonchelation‐controlled addition products 7 and 36, respectively (stereoselectivity 95:5, 86:14). These results provide a route to oligo(tetrahydrofuran)s with the relative stereochemistry trans‐syn‐cis. A stereodirecting effect of the chiral center in the organozinc reagent 17 is found, leading to simple diastereoselectivies in the reaction with achiral aldehydes and to a matched‐mismatched case in the reaction with the chiral aldehyde 1.