Studies on Cu(I)-catalyzed synthesis of simple 3-substituted 1,2-allenes and optically active 2-substituted secondary 2,3-allenols
作者:Jing Li、Chao Zhou、Chunling Fu、Shengming Ma
DOI:10.1016/j.tet.2009.02.061
日期:2009.5
methyl ethers, which would react with primary alkyl Grignard reagents under the catalysis of CuBr to afford 3-substituted 1,2-allenes or 2-substituted secondary 2,3-allenols, respectively. The reaction may be applied to the synthesis of optically active 2-substituted secondary 2,3-allenols with up to >99% ee without any protection to the free hydroxyl group in the starting 4-hydroxy-2-alkynyl methyl
Efficient two-step synthesis of 3-halo-3-enals or 2-halo-2-alkenyl ketones from propargylic bromides via a unique cationic 1,2-aryl or proton shift in electrophilic addition reaction of 2,3-allenols with X+
作者:Chunling Fu、Jing Li、Shengming Ma
DOI:10.1039/b508069j
日期:——
The reaction of readily available 1-substituted 2,3-allenols with Br2, NBS, or I2 afforded the not-easily-available but synthetically useful 3-halo-3-alkenals or 2-halo-2-alkenyl ketones in good yields via a sequential electrophilic interaction of X+ with the allene moiety , a 1,2-aryl or proton shift, and a H+-elimination process; the structures of the products were established by X-ray diffraction
Asymmetric semipinacol rearrangement of 2,3-allenols with N-bromo-1,8-naphthalimide
作者:Binjie Guo、Chunling Fu、Shengming Ma
DOI:10.1039/c4cc00767k
日期:——
A method using quinidine and optically active binol-derived phosphoric acid as a cocatalyst to catalyze the asymmetric semipinacol rearrangement of 2,3-allenols forming optically active 3-bromo-3-enals that contain an all-carbon quaternary stereocenter has been developed. After some further treatments, the products with practical enantiomeric purity could be prepared.