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
Carbazoles from the [4C+2C] Reaction of 2,3-Allenols with Indoles
作者:Binjie Guo、Xin Huang、Chunling Fu、Shengming Ma
DOI:10.1002/chem.201604317
日期:2016.12.19
A mild and efficient method using readily available 1‐aryl‐2,3‐allenols and unprotected‐N indoles, Au+‐catalyzed cyclization, and aromatization to afford the final [4C+2C] products, carbazoles 4, with an excellent selectivity, is reported. The reaction demonstrates excellent regioselectivity and allows the N−H unit to undergo reactivity unprotected. A mechanism involving a spiropolycyclic intermediate
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.