Co-Investigator(Kenkyū-buntansha) |
OHMORI Hidenobu Osaka University, Graduate School of Pharmacology ; Professor, 大学院・薬学研究科, 教授 (90028845)
NONAKA Tsutomu Turuoka National College of Technology ; Principle, 校長 (00016528)
MAEKAWA Hirofumi Nagaoka University of Technology, Faculty of Engineering ; Assistant Professor, 工学部, 助手 (70283041)
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Research Abstract |
In this study, highly regio- and stereoselective carbon-carbon and carbon-silicon bonds formations, which cannot be observed in a homogeneous solution, have been developed through dynamic control of stereochemistry of reactive intermediates generated on a heterogeneous interface between solid and liquid by electron transfer reactions from metals or electrodes to organic compounds. For example, treatment of 3-alkylcoumarins as typical aromatic α,β-unsaturated esters with acid anhydrides in the presence of easily available Mg turning without any pre-treatment brought about highly regio- and stereoselective C-acylation to give the thermodynamically unfavorable cis-3-alky-4-acyldihydrocoumarins with stereo-selectivity of 92-98%. Under the similar reaction conditions, high regio- and stereoselectivities were also observed in the Mg-promoted silylation of 3-alkylcoumarins and dimethyl 1,2-dihydro-2,3-pyridinedicarboxylates. On the other hand, (Z)- and (E)-3-buten-1-ols were exclusively obtained in the stereospecific manner from electroreductive ring-cleavage of cis- and trans- 2-substituted-3-chlorotetrahydrofurans, respectively. Furthermore, electroreduction of methyl trichloroacetate in the presence of aliphatic aldehydes using a reactive Zn anode resulted in stereoselective corss-coupling giving (Z)-α-chloroglycidyl esters. Also, remarkable stereoselectivity control by irradiation of ultrasounds onto the electorode surface was successfully established in the electroreductive dimerization of acetophenone and debromination of dl-1,2-dibromoethanes.
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