Functionalized Diorganozinc Compounds: Key Reagents for the Synthesis of Enantiomerically Pure 2,5‐Disubstituted cis‐ and trans‐Tetrahydrofurans

Abstract 1,4‐Diol derivatives 4a‐i were synthesized stereoselectively by either reagent‐ or catalyst‐controlled routes using the addition of functionalized diorganozinc reagents to aldehydes. The stereoselectivities along the reagent‐controlled synthetic path were in the range between 80:20 and 95:5. The stereoselectivities along the catalyst route exceeded 95:5. The 1,4‐diol derivatives 4 thus obtained were transformed into enantiomerically pure cis‐ and trans‐2,5‐disubstituted tetrahydrofurans (16‐20) by means of an intramolecular Williamson reaction.