Electrochemical oxidative radical cascade cyclization of olefinic amides and thiophenols towards the synthesis of sulfurated benzoxazines, oxazolines and iminoisobenzofurans
containing N and O are important structures in pharmaceuticals, agrochemicals and functional molecules. The synthesis of these compounds usually requires complex substrates and harsh reaction conditions. Herein, we introduce a mild and efficient electrochemical oxidative strategy to construct benzoxazines, oxazolines and iminoisobenzofurans without the requirement of a transition-metal catalyst and an
含 N 和 O 的杂环是药物、农用化学品和功能分子中的重要结构。这些化合物的合成通常需要复杂的底物和苛刻的反应条件。在此,我们引入了一种温和有效的电化学氧化策略来构建苯并恶嗪、恶唑啉和亚氨基异苯并呋喃,而无需过渡金属催化剂和外部氧化剂。在一个简单的未分开的细胞中,各种烯酰胺和苯硫酚/二硒化物反应生成 69 个硫醇化和硒化杂环的例子,产率高达 83%。此外,这种自由基级联反应为一步构建 C-S/C-Se 和 C-O 键提供了一种简便的方法。
Amides as precursors of imidoyl radicals in cyclisation reactions
作者:W. Russell Bowman、Anthony J. Fletcher、Jan M. Pedersen、Peter J. Lovell、Mark R.J. Elsegood、Elena Hernández López、Vickie McKee、Graeme B.S. Potts
DOI:10.1016/j.tet.2006.10.030
日期:2007.1
Amides have been successfully used as precursors of imidoyl radicals for radical cyclisation. The amides have been converted to imidoyl selanides via reaction with phosgene to yield imidoyl chlorides followed by reaction with potassium phenylselanide. Imidoyl selanides were reacted with tributyltin hydride (Bu3SnH) as the radical mediator with triethylborane or AIBN as initiators to yield imidoyl radicals
XtalFluor-E® mediated proto-functionalization of <i>N</i>-vinyl amides: access to <i>N</i>-acetyl <i>N</i>,<i>O</i>-acetals
作者:Y. Yi、H. Gholami、M. G. Morrow、B. Borhan
DOI:10.1039/c7ob02283b
日期:——
few years. Here we report its use with protic nucleophiles in a catalytic manner for the in situ generation of protons that lead to the proteo functionalization of activated olefins. Utilizing the latter protocol, proteo etherification of enamides gives rise to N,O-acetals in nearly quantitative yields.
The synthesis of 5-[(pentafluorosulfanyl)methyl]-2-oxazolines is reported. The use of a silver promoter allows the intramolecular cyclization of N-[2-chloro-3-(pentafluorosulfanyl)propyl]amide to occur without elimination of the chlorine atom, a reaction pathway typically observed for β-chloro-SF5-alkyl compounds. The products, potentially valuable SF5-containing heterocycles, are obtained in up to
Iodine-promoted cyclization of N-propynyl amides and N-allyl amides via sulfonylation and sulfenylation
作者:Gopal Chandru Senadi、Bing-Chun Guo、Wan-Ping Hu、Jeh-Jeng Wang
DOI:10.1039/c6cc05138c
日期:——
Iodine-promoted sulfonylation of N-propynyl amides with sulfonyl hydrazides followed by DBU mediated cyclisation to afford 5-methyl-arylsulfonyloxazoles and oxysulfenylation of N-allyl amides through electrophilic addition of in situ generated sulfenyl iodide...