Stereoselective Synthesis of Alcohols, XLII. Stereoselective Cyclization of (8‐Oxo‐2‐octenyl)boronates to cis‐ or trans‐2‐Vinylcyclohexanol

Intramolecular allylboration reactions of (8‐oxo‐2‐octenyl)boronates proceed with excellent diastereoselectivity: the E‐isomer 1d leads to the trans‐2‐vinylcyclohexanol (2) with 99.5% d.s., the corresponding Z‐isomer 3d cyclizes to give the cis‐isomer with a diastereoselectivity exceeding 99.8%.