Unraveling the reaction mechanism, enantio and diastereoselectivities of selenium ylide promoted epoxidation
نویسندگان
چکیده
Madhavan Jaccob , Gopal Sabapathi, J Vijaya Sundar, P Kolandaivel *, V Subramanian * & Ponnambalam Venuvanalingam * Theoretical and Computational Chemistry Laboratory, School of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India Email: [email protected] Chemical Laboratory, CSIR-Central Leather Research Institute, Adyar, Chennai 600 020, Tamil Nadu, India Email: [email protected] Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India Email: [email protected]
منابع مشابه
The complexity of catalysis: origins of enantio- and diastereocontrol in sulfur ylide mediated epoxidation reactions.
The reaction of chiral sulfur ylides with aldehydes and ketones has emerged as a useful asymmetric process for the synthesis of epoxides. Processes employing either catalytic or stoichiometric amounts of sulfides have been developed. Although a large number of chiral sulfur ylides have been tested in the epoxidation process, only a few have delivered high diastereo- and enantio- selectivity. Th...
متن کاملPractical and highly selective sulfur ylide-mediated asymmetric epoxidations and aziridinations using a cheap and readily available chiral sulfide: extensive studies to map out scope, limitations, and rationalization of diastereo- and enantioselectivities.
The chiral sulfide, isothiocineole, has been synthesized in one step from elemental sulfur, γ-terpinene, and limonene in 61% yield. A mechanism involving radical intermediates for this reaction is proposed based on experimental evidence. The application of isothiocineole to the asymmetric epoxidation of aldehydes and the aziridination of imines is described. Excellent enantioselectivities and d...
متن کاملA Highly Diastereoselective and Enantioselective Phase-Transfer Catalyzed Epoxidation of β-Trifluoromethyl-β,β-disubstituted Enones with H2O2
Trifluoromethylated organic compounds, especially chiral quaternary alcohols bearing trifluoromethyl group are of important intermediates in drugs, agrochemicals and etc.An efficient epoxidation of β-CF3-β,β-disubstituted unsaturated ketones (6) has been developed with environmental benign hydrogen peroxide as the oxidant and F5-substituted chiral qua...
متن کاملPractical and highly selective sulfur ylide mediated asymmetric epoxidations and aziridinations using an inexpensive, readily available chiral sulfide. Applications to the synthesis of quinine and quinidine.
Heating one of the most abundant naturally occurring inorganic chemicals (elemental sulfur) with one of the most readily available homochiral molecules (limonene) gives a one-step synthesis of a chiral sulfide which exhibits outstanding selectivities in sulfur ylide mediated asymmetric epoxidations and aziridinations. In particular reactions of benzyl and allylic sulfonium salts with both aroma...
متن کاملSynthesis of quinine and quinidine using sulfur ylide-mediated asymmetric epoxidation as a key step
Article history: Received 13 April 2010 Accepted 28 April 2010 Available online 16 June 2010 Dedicated to Henri Kagan on the occasion of his 80th birthday 0957-4166/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.tetasy.2010.04.046 * Corresponding author. Tel.: +44 117 954 6315; fa E-mail address: [email protected] (V.K. Agg The epoxidation of meroquinene aldehyde with a chiral sul...
متن کامل