Nucleophilic substitution gone awry: A novel cyclopropanation reaction with a surprising stereochemical outcome

Article abstract of DOI:10.1016/0040-4039(95)01192-K

Lithium triethylborohydride reacts with the triisopropylbenzene sulfonate ester of 2-methoxy-5,5-dimethyl-2-vinyl-3-cyclohexen-1-ol (1) to afford 8-methoxy-6,6-dimethylspiro[2.5]oct-4-ene (3). Labeling studies reveal that this novel cyclopropane forming reaction proceeds with retention of configuration at the newly formed quaternary center.