Stereoselective Synthesis of<i>Z</i>-Styryl Sulfides from Nucleophilic Addition of Arylacetylenes and Benzyl Thiols
Tarun Kumar Dinda, Syed Ramizul Kabir, Prasenjit Mal
Abstract
The stereoselective synthesis of Z-anti -Markovnikov styryl sulfides via an anionic thiolate–alkyne addition reaction was achieved when the terminal alkynes and benzyl mercaptans were reacted using t BuOLi (0.5 equiv) in EtOH under ambient conditions. Exclusive stereoselectivity (ca. 100%) was achieved by stereoelectronic control via anti -periplanar and anti -Markovnikov addition of benzylthiolates to phenylacetylenes. Solvolysis of lithium thiolate ion pairs in ethanol significantly suppresses the competing formation of the E- isomer. A remarkable enhancement of the Z -selectivity under a longer reaction time was observed.
Topics & Concepts
Markovnikov's ruleChemistryStereoselectivitySolvolysisMedicinal chemistryNucleophileOxonium ionAlkyneButyllithiumNucleophilic additionSelectivityOrganic chemistryIonRegioselectivityCatalysisHydrolysisSulfur-Based Synthesis TechniquesChemical Synthesis and ReactionsSynthesis and Catalytic Reactions