Palladium-Catalyzed Carbene Coupling Reactions of Cyclobutanone <i>N</i>-Sulfonylhydrazones
作者:Xiaoqin Ning、Yongke Chen、Fangdong Hu、Ying Xia
DOI:10.1021/acs.orglett.1c03052
日期:2021.11.5
Described herein are the palladium-catalyzed cross-couplingreactions of cyclobutanone-derived N-sulfonylhydrazones with aryl or benzyl halides, suggesting that the metal carbene process and β-hydride elimination can smoothly occur in strained ring systems. Structurally diversified products including cyclobutenes, methylenecyclobutanes, and conjugated dienes are selectively afforded in good to excellent
A visible-light-driven and room temperature photo-Wolff-Kischner reaction of sulfur ylides and N-tosylhydrazones has been developed for the first time to provide modular access to alkene synthesis. The high functional group tolerance and broad substrate scope were demonstrated by more than 60 examples. Both E- and Z-olefinic stereochemistry in the products could be controlled with excellent stereoselectivity
Photo‐Induced Homologation of Carbonyl Compounds for Iterative Syntheses
作者:Hua Wang、Shun Wang、Vincent George、Galder Llorente、Burkhard König
DOI:10.1002/anie.202211578
日期:2022.12.5
A photo-induced Büchner-Curtius-Schlotterbeck type reaction for carbonyl homologation is described. The protocol allows the use of carbonyl compounds as safe and readily available diazo precursors through direct photoexcitation of corresponding N-tosylhydrazone anions. Functionalized aliphatic aldehydes and ketones are prepared in a practical and iterative manner.
Photogenerated donor–donor diazo compounds enable facile access to spirocyclopropanes
作者:Vincent George、Burkhard König
DOI:10.1039/d3cc03581f
日期:——
Prompted by the increasing interest in strained hydrocarbons as potential drug candidates, we developed a simple and efficient photochemical protocol for (spiro)cyclopropanes from bench stable tosylhydrazones and electron poor olefins. This two-step one-pot transformation proceeds by (3+2)-cycloaddition of in situ formed donor–donor diazo compounds, followed by nitrogen extrusion of the Δ1-pyrazoline
Polycyclic Pyrazoles from Alkynyl Cyclohexadienones and Nonstabilized Diazoalkanes via [3 + 2]-Cycloaddition/[1,5]-Sigmatropic Rearrangement/Aza-Michael Reaction Cascade
center substituted” polycyclic pyrazoles from alkynyl cyclohexa-2,5-dienones and nonstabilized diazoalkanes via sequential [3 + 2]-cycloaddition/[1,5]-sigmatropic rearrangement and aza-Michael reactions is reported. The developed process is highly regioselective and stereoselective. It employs a wide substrate scope to furnish structurally diverse linear and bridged [4.4.n.0] ring-fused pyrazoles in moderate
一种通过连续[3 + 2]-环加成/[1,5]-σ重排和氮杂-迈克尔反应从炔基环己-2,5-二烯酮和不稳定重氮烷立体选择性合成“全中心取代”多环吡唑的有效方法被报道。所开发的过程具有高度区域选择性和立体选择性。它采用广泛的基材范围来提供结构多样的线性和桥接[4.4。 n .0]稠环吡唑,产率中等至良好。还展示了一锅法和克级合成以及合成转化。