1124258-50-9Relevant academic research and scientific papers
New general method for regio- and stereoselective allylic substitution with aryl and alkenyl coppers derived from grignard reagents
Kiyotsuka, Yohei,Katayama, Yuji,Acharya, Hukuni P.,Hyodo, Tomonori,Kobayashi, Yuichi
scheme or table, p. 1939 - 1951 (2009/08/07)
Allylic substitution with sp2-carbon reagents (aryl and alkenyl anions) was realized by using allylic picolinates and copper reagents derived from RMgBr and CuBr-Me2S to afford anti SN2 products regioand stereoselectively. Steric and electronic factors in the reagents and the size of the methylene substituents around the allylic moiety marginally affected the selectivity. The reaction system was compatible with alkyl reagents as well. Furthermore, the substitution was applied to construction of a quaternary center and synthesis of (-)-sesquichamaenol. Electron-withdrawing nature of the pyridyl group and chelation of the C(=O)-C5H4N to MgBr2 generated in situ were found to be responsible for the high efficiency of the substitution.
Picolinoxy group, a new leaving group for anti SN2 selective allylic substitution with Aryl Anions Based on Grignard Reagents
Kiyotsuka, Yohei,Acharya, Hukum P.,Katayama, Yuji,Hyodo, Tomonori,Kobayashi, Yuichi
body text, p. 1719 - 1722 (2009/04/10)
The picolinoxy group was found to be an extremely powerful leaving group for allylic substitution with aryl nucleophiles derived from ArMgBr and CuBr?Me2S. The substitution proceeds with anti SN2 pathway and with high chirality transfer. The electron-withdrawing effect of the pyridyl group and chelation to MgBr2 are likely the origin of success. Results suggesting these effects were obtained.
