Study on halolactamization-γ-hydroxylation or haloiminolactonization of 2,3-alkadienamides
摘要:
The reactions of 4-mono- or 4-unsubstituted 2,3-alkadienamides with CuX2 afforded 5-hydroxypyrTol-2(5H)-ones via the sequential lactamization and gamma-hydroxylation process in aqueous THF while those of 4,4-disubstituted 2,3-alkadienamides with CuX2 in THF afforded iminolactones in high yields. Iodoiminolactonization and iodolactamization/gamma-hydroxylation were achieved by the corresponding reaction with I-2 in THF at rt. The structures of the products depend on the steric hindrance at the 4-position of the starting allenamides. Relatively electron-rich allenes afforded the corresponding products in much higher yields under milder reaction conditions implying the intramolecular electrophilic nature of the cyclization reaction. (C) 2004 Elsevier Ltd. All rights reserved.
Amide-Controlled Highly Selective Catalytic Borylcupration of Allenes
作者:Weiming Yuan、Xue Zhang、Yihua Yu、Shengming Ma
DOI:10.1002/chem.201202835
日期:2013.5.27
A novel copper‐catalyzed, highly regio‐ and stereoselective borylcupration of substituted 2,3‐allenamides with bis(pinacolato)diboron producing Z‐β‐borylated β,γ‐unsaturated enoamides has been demonstrated. Due to the unique effect of the amide‐group, perfect regio‐ and stereoselectivity and good to excellent yields have been achieved, which were rationalized by a DFT study.
A Novel Synthesis of 1,3-Oxazine-2,4-diones via a Simple and Efficient Reaction of CO<sub>2</sub> with 2,3-Allenamides
作者:Guofei Chen、Chunling Fu、Shengming Ma
DOI:10.1021/ol9009046
日期:2009.7.2
A simple and efficient reaction of CO2 with 2,3-allenamides under mild conditions (CO2 balloon without any metal catalyst in the presence of K2CO3 or Cs2CO3) leads to an efficient synthesis of 1,3-oxazine-2,4-diones. The high reactivity of the allene moiety is crucial for the success of this transformation since the corresponding reaction of alpha,beta-unsaturated alkenamides or alkynamides does not occur.
Access to 1,3-oxazine-2,4-diones/1,3-thiazine-2,4-diones <i>via</i> organocatalytic CO<sub>2</sub>/COS incorporation into allenamides
作者:Hui Zhou、Rui Wang、Hui Zhang、Wei Chen、Xiao-Bing Lu
DOI:10.1039/c9ob02398d
日期:——
Lewis base-CO2/COS adducts were firstly studied as organocatalysts for [4 + 2] annulation of CO2/COS with allenamides to selectively synthesize 1,3-oxazine-2,4-diones/1,3-thiazine-2,4-diones.
Study on halolactamization-γ-hydroxylation or haloiminolactonization of 2,3-alkadienamides
作者:Shengming Ma、Hexin Xie
DOI:10.1016/j.tet.2004.10.050
日期:2005.1
The reactions of 4-mono- or 4-unsubstituted 2,3-alkadienamides with CuX2 afforded 5-hydroxypyrTol-2(5H)-ones via the sequential lactamization and gamma-hydroxylation process in aqueous THF while those of 4,4-disubstituted 2,3-alkadienamides with CuX2 in THF afforded iminolactones in high yields. Iodoiminolactonization and iodolactamization/gamma-hydroxylation were achieved by the corresponding reaction with I-2 in THF at rt. The structures of the products depend on the steric hindrance at the 4-position of the starting allenamides. Relatively electron-rich allenes afforded the corresponding products in much higher yields under milder reaction conditions implying the intramolecular electrophilic nature of the cyclization reaction. (C) 2004 Elsevier Ltd. All rights reserved.