Highly Diastereoselective Preparation of Tertiary Alkyl Thiocyanates en Route to Thiols by Stereoinvertive Nucleophilic Substitution at Nonclassical Carbocations

An effective InBr₃-catalyzed nucleophilic thiocyanation of cyclopropyl alcohols has been developed. The reaction takes place at the quaternary carbon stereocenter of the cyclopropyl carbinol with a complete inversion of configuration, offering a novel pathway for the creation of complex tertiary alkyl thiocyanates with high diastereopurity. These substitution reactions proceed under mild reaction conditions and tolerate several functional groups. Additionally, thiocyanates were converted to thiols using lithium aluminum hydride.