Enantioselective Intermolecular [2+2] Photocycloaddition Reaction of Cyclic Enones and Its Application in a Synthesis of (−)-Grandisol
作者:Saner Poplata、Thorsten Bach
DOI:10.1021/jacs.8b01011
日期:2018.3.7
The intermolecular [2+2] photocycloaddition of typical cyclic α,β-unsaturated enones, such as 2-cyclohexenone, with olefins was performed in moderate to good yields (42–82%) and with high enantioselectivity (82%–96% ee). An unusual substitution pattern at the chiral oxazaborolidine-AlBr3 Lewisacid complex that promotes the reaction was found to be crucial for the success of the reaction. The method
典型的环状 α,β-不饱和烯酮(如 2-环己烯酮)与烯烃的分子间 [2+2] 光环加成以中等至良好的产率(42-82%)和高对映选择性(82%-96% ee )。发现促进反应的手性恶唑硼烷-AlBr3 路易斯酸络合物的不寻常取代模式对反应的成功至关重要。该方法用于对映选择性合成单萜(-)-格兰地醇,以3-甲基-2-环己烯酮为原料,可分六步完成,总产率为13%。
Cyclopropylcarbinyl radical-mediated ring expansion to seven-membered carbocycles
作者:Eric J. Kantorowski、Babak Borhan、Saman Nazarian、Mark J. Kurth
DOI:10.1016/s0040-4039(98)00311-6
日期:1998.4
carbocycles can be prepared from the corresponding xanthate derivatives of bicyclo[4.1.0]heptan-1-methanol. In certain systems, an intermediate cycloheptyl radical appears to be kinetically favored over the cyclohexyl radical, but the direction of cyclopropylcarbinyl radical fragmentation is subject to substitution about the bicyclo[4.1.0]heptan-1-methyl ring.
Diiodomethane-Mediated Generation of <i>N</i>-Aryliminium Ions and Subsequent [4 + 2] Cycloadditions with Olefins
作者:Yu-Quan Zhao、Jun-Jie Tian、Chong-Ren Ai、Xiao-Chen Wang
DOI:10.1021/acs.joc.9b03148
日期:2020.2.21
between N,N-dimethylanilines, diiodomethane, and olefins. This transformation involves initial reaction of the aniline with diiodomethane to form an iodomethylammonium salt, which undergoes fragmentation accompanied by elimination of methyl iodide to give an N-aryliminium ion, which is trapped by the olefin via [4 + 2] cycloaddition to give the final product. This method for generating N-aryliminium ions
Enecarboxylation with diethyl oxomalonate as an enophilic equivalent of carbon dioxide. A synthesis of allylcarboxylic acids
作者:Mary F. Salomon、Simon N. Pardo、Robert G. Salomon
DOI:10.1021/ja00325a014
日期:1984.6
On prepare une serie d'acides carboxyliques allyliques a partir des olefines correspondantes par un processus en deux etapes equivalent a: 1) une reaction ene avec l'oxomalonate de diethyle conduisant a l'ester α-hydroxymalonique; 2) une bisdecarboxylation oxydante de ce dernier
在制备 une serie d'acides carboxyliques allyliques a partir des ocoxyliques par un processus en deux etapes 等价物 a: 1) une 反应 ene avec l'oxomalonate de diethyle conduisant a l'ester α-hydroxymalonique; 2) une bisdecarboxylation oxydante de ce dernier
Synthesis of Bridged Azacycles and Propellanes via Nitrene/Alkyne Cascades
作者:Qinxuan Wang、Jeremy A. May
DOI:10.1021/acs.orglett.0c00798
日期:2020.4.17
nitrene tether showed that 7-membered rings were the maximum ring size to be formed by nitrene attack on the alkyne. Examples incorporating stereocenters on the carbonazidate’s tether induced diasteroselectivity in the formation of the bridgedring and two new stereocenters. Additionally, propellanes containing aminals, hemiaminals, and thioaminals formed from the bridged azacycles in the same reaction via