Electrochemically driven desaturation of carbonyl compounds
作者:Samer Gnaim、Yusuke Takahira、Henrik R. Wilke、Zhen Yao、Jinjun Li、Dominique Delbrayelle、Pierre-Georges Echeverria、Julien C. Vantourout、Phil S. Baran
DOI:10.1038/s41557-021-00640-2
日期:2021.4
reagent. This electrochemically driven desaturation exhibits a broad scope across an array of carbonyl derivatives, is easily scalable (1–100 g) and can be predictably implemented into synthetic pathways using experimentally or computationally derived NMR shifts. Systematic comparisons to state-of-the-art techniques reveal that this method can uniquely desaturate a wide array of carbonyl groups. Mechanistic
长期以来,电化学技术因其与生俱来的可持续性而被誉为实现氧化还原反应的有效方法。作为一种基本的有机氧化,羰基去饱和是一种常用的转化方法,通过正式去除两个氢原子来解锁相邻的反应性。迄今为止,实现这种看似微不足道的反应的最可靠方法依赖于过渡金属(Pd 或 Cu)或基于 I、Br、Se 或 S 的化学计量试剂。在这里,我们报告了一种操作简单的途径,可以从烯醇硅烷和以电子为主要试剂的磷酸盐。这种电化学驱动的去饱和在一系列羰基衍生物中表现出广泛的范围,易于扩展(1-100 g),并且可以使用实验或计算得出的 NMR 位移可预测地实施到合成途径中。与最先进技术的系统比较表明,这种方法可以独特地使各种羰基去饱和。机械审讯表明基于自由基的反应途径。
Synthesis of (Difluoromethyl)cycloalkenes from 2‐Cycloalkenones by Utilizing Phospha‐Brook Rearrangement
Difluoromethyl‐substituted allylicphosphates were synthesized from 2‐cycloalkenones through the addition of a (difluoromethyl)phosphonate and subsequent phospha‐Brook rearrangement. The obtained allylicphosphates were converted to the corresponding difluoromethyl‐substituted cycloalkenes using the Cu‐mediated SN2’ reaction of Grignard or organolithium reagents.
通过添加(二氟甲基)膦酸酯和随后的Pha-Brook重排,由2-环烯酮合成二氟甲基取代的烯丙基磷酸酯。使用格氏试剂或有机锂试剂的Cu介导的S N 2'反应,将获得的烯丙基磷酸酯转化为相应的二氟甲基取代的环烯烃。
Synthesis of Cyclic Enones via Direct Palladium-Catalyzed Aerobic Dehydrogenation of Ketones
作者:Tianning Diao、Shannon S. Stahl
DOI:10.1021/ja206575j
日期:2011.9.21
carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds. Here, we report the discovery and application of Pd(DMSO)(2)(TFA)(2) as a catalyst for direct dehydrogenation of cyclohexanones and other cyclicketones to the corresponding enones, using O(2) as the oxidant. The substrate scope includes heterocyclic ketones and several natural-product
Platinum‐Catalyzed Desaturation of Lactams, Ketones, and Lactones
作者:Ming Chen、Alexander J. Rago、Guangbin Dong
DOI:10.1002/anie.201811197
日期:2018.12.3
desaturation of N‐protected lactams, ketones, and lactones to their conjugated α,β‐unsaturated counterparts is reported. The reaction operates under mildly acidic conditions at room temperature or 50 °C. It is scalable and tolerates a wide range of functional groups. The complementary reactivity to the palladium‐catalyzed desaturation is demonstrated in the efficient conversion of iodide, bromide, and sulfur‐containing
Applications of the β-Azidonation Reaction to Organic Synthesis. α,β-Enones, Conjugate Addition, and γ-Lactam Annulation
作者:Philip Magnus、Jérôme Lacour、P. Andrew Evans、Pascal Rigollier、Hans Tobler
DOI:10.1021/ja9829564
日期:1998.12.1
The β-azido functionalization reaction provides a mechanistically different enone synthesis that involves treatment of 2 with fluoride anion to effect desilylation and concomitant β-elimination to give 3. Table 1 lists a number of examples of the direct conversion of a TIPS enolether into the corresponding α,β-enone via a β-azido TIPS enolether. The β-azido group can be ionized with Me3Al or Me2AlCl