Tin-Free Enantioselective Radical Reactions Using Silanes
摘要:
Readily available hexyl silane is an excellent choice as a H-atom donor and a chain carrier in Lewis acid mediated enantioselective radical reactions. Conjugate radical additions to alpha,beta-unsaturated imides at room temperature proceed in good yields and excellent enantioselectivities.
Synthesis of mixed acyclic imides using pentafluorophenyl esters
作者:Merritt B. Andrus、Wenki Li、Robert F. Keyes
DOI:10.1016/s0040-4039(98)01112-5
日期:1998.7
Mixed acyclicimides are assembled using amide anions and pentafluorophenyl esters reacted in THF at low temperature. Sodium hexamethyldisilazide deprotonates lactam 4 followed by addition of pentafluorophenyl (PFP) esters to give imides in high yield (85–90%). Acyclic TMS-protected primary amides were also reacted under basic conditions with PFP esters to give mixed imides.
Enantioselective Radical Methods for Lactone Synthesis: Use of Unprotected Haloalcohols as Radical Precursors
作者:Mukund P. Sibi、Miguel A. Guerrero
DOI:10.1055/s-2005-865319
日期:——
We have developed an efficient free radical method for the synthesis of enantioenriched 6- and 7-membered lactones in one synthetic operation.
我们开发了一种高效的自由基方法,可在一次合成操作中合成对映体丰富的 6 元和 7 元内酯。
One pot transamidation of <i>N</i>-pivaloyl activated amides with anilines in the absence of catalyst, base and additive
作者:Ida Angel Priya Samuel Rajan、Saravanakumar Rajendran
DOI:10.1039/d3nj01490h
日期:——
Transamidation of N-pivaloyl activated amides with weakly-nucleophilic amines such as anilines is demonstrated in the absence of catalyst, base and additives. Under the one-pot conditions, amides were activated in situ by the pivaloyl group and were reacted with anilines at toluene reflux temperature to obtain transamidation products in moderate to excellent yields (60–97%).
Tin-Free Enantioselective Radical Reactions Using Silanes
作者:Mukund P. Sibi、Yong-Hua Yang、Sunggi Lee
DOI:10.1021/ol802154d
日期:2008.12.4
Readily available hexyl silane is an excellent choice as a H-atom donor and a chain carrier in Lewis acid mediated enantioselective radical reactions. Conjugate radical additions to alpha,beta-unsaturated imides at room temperature proceed in good yields and excellent enantioselectivities.
Amidic resonance not a barrier for transamidation of <i>N</i>-pivaloyl activated amides: catalyst, base and additive free conditions
作者:Ida Angel Priya Samuel Rajan、Saravanakumar Rajendran
DOI:10.1039/d3ob00418j
日期:——
stabilized N-pivaloyl activatedamides is demonstrated in the absence of a catalyst, base and additive. Furthermore, C–N (1.374 Å) and CO (1.222 Å) bond lengths indicate the existence of amidic resonance; yet, transamidation is achieved at roomtemperature with alkyl amines in a short reaction time (0.5–2 h) with 60–97% yield. Amines bearing protic hydroxy and carboxylicacid groups were tolerated
在没有催化剂、碱和添加剂的情况下证明了无扭曲(扭曲角 ( τ ) = 4.54°)和共振稳定的N-新戊酰活化酰胺的转酰胺基作用。此外,C–N (1.374 Å) 和 C O (1.222 Å) 键长表明存在酰胺共振;然而,转酰胺基反应是在室温下用烷基胺在短反应时间(0.5-2 小时)内实现的,产率为 60-97%。在反应条件下可以容忍带有质子羟基和羧酸基团的胺。因此,我们的研究结果表明N -新戊酰基激活的平面和共振稳定的酰胺对亲核加成具有足够的反应性。