1-Methylgeraniol as Novel Regio- and Diastereoselective Probe for Hydrogen Bonding in Hydroxy-Assisted Oxygen-Transfer Reactions

The chiral 1‐methylgeraniol has been designed and applied for epoxidation reactions as a mechanistic probe, which allows to assess simultaneously in one and the same molecule regio‐ and stereochemical information. Of the two trisubstituted double bonds, the terminal 7,8 one reflects kinetic preferences on account of its greater π nucleophilicity, the 3,4 one with the chiral allylic hydroxy functionality expresses diastereoselective directivity through hydrogen bonding. The combination of regio‐ and stereoselectivity provides a novel and powerful mechanistic tool to differentiate electronic and steric effects of oxidants. Thus, various epoxidizing agents have been employed and the mechanistic implications derived from the product ratios are well in line with those reported, which exemplifies the validity of the probe.