Aqueous Compatible Protocol to Both Alkyl and Aryl Thioamide Synthesis
作者:Jianpeng Wei、Yiming Li、Xuefeng Jiang
DOI:10.1021/acs.orglett.5b03541
日期:2016.1.15
An efficient aqueous synthesis of thioamides through aldehydes, sodium sulfide, and N-substituted formamides has been developed. Both alkyl and aryl aldehydes are amenable to this protocol. N-Substituted formamides are essential for this transformation. Readily available inorganic salt (sodium sulfide) serves as the sulfur source in water, which makes this method much more practical and efficient.
Practical and Convenient Synthesis of <i>N</i>-Heterocycles: Stereoselective Cyclization of <i>N</i>-Alkenylamides with <i>t</i>-BuOI under Neutral Conditions
[Structure: see text] tert-Butylhypoiodite (t-BuOI) was found to be a powerful reagent for the cyclization of N-alkenylamides leading to a variety of N-heterocycles under extremely mild conditions. When N-alkenylsulfonamides were employed in the reaction, three- to six-membered saturated N-heterocycles were obtained in good to excellent yields with complete stereoselectivity. The method was applicable
for transamidation of thioamides by N−C(S) transacylation is reported. This process exploits the concept of site-selective N-tert-butoxycarbonyl activation, resulting in ground-state-destabilization of thioamides. The study establishes a powerful direction to the development of new molecules in chemistry and biology by rational modification of nN→π*C=S resonance of the thioamide bond.
报道了第一种通过 NC(S) 转酰基作用对硫代酰胺进行转酰胺基作用的通用、温和且高度化学选择性的方法。该过程利用了位点选择性 N-叔丁氧羰基活化的概念,导致硫代酰胺的基态不稳定。该研究通过对硫代酰胺键的n N →π* C=S共振进行合理修饰,为化学和生物学新分子的发展奠定了有力的方向。
Time-economical synthesis of selenofunctionalized heterocycles <i>via</i> I<sub>2</sub>O<sub>5</sub>-mediated selenylative heterocyclization
A time-economical and robust synthesis of various selenofunctionalized heterocycles was accomplished via I2O5-mediated selenocyclizations of olefins with diselenides. Using this method, 116 selenomethyl-substituted heterocycles were synthesized with up to 97% isolated yield in minutes. Additional features of this new protocol include the use of an inorganic oxidant, mild conditions, and easy operation
通过I 2 O 5介导的烯烃与二硒化物的硒环化,实现了各种硒官能化杂环的经济且稳健的合成。使用这种方法,在几分钟内合成了 116 个硒甲基取代的杂环,分离产率高达 97%。这个新协议的其他特点包括使用无机氧化剂、温和的条件和易于操作。初步研究表明,这种转化是通过硒基碘诱导的亲电环化进行的。
Electrochemical Chalcogenation of
<i>β,γ</i>
‐Unsaturated Amides and Oximes to Corresponding Oxazolines and Isoxazolines
作者:Samrat Mallick、Mrinmay Baidya、Kingshuk Mahanty、Debabrata Maiti、Suman De Sarkar
DOI:10.1002/adsc.201901262
日期:2020.3.4
The current report represents a transition‐metal‐freesynthesis of oxazoline and isoxazoline derivatives by a tandem electro‐oxidative chalcogenation‐cyclization process. Both C−Se and C−S bond‐forming protocols were developed without using any external oxidant and the reaction was performed at roomtemperature, open to the air. Using this methodology, 29 substituted oxazoline and 16 substituted isoxazoline