在本文中,我们报道了在炔基砜存在下,通过臭氧介导和 Fe II催化的未活化烯烃的脱烯基炔基化合成烷基链炔烃。这种一锅反应采用催化 Fe II盐和L-抗坏血酸的组合,在温和的条件下进行,具有良好的效率、高立体选择性和广泛的官能团兼容性。与我们之前的 Fe II介导的 α-甲氧基氢过氧化物还原断裂相比,Fe II催化的过程是通过对多个竞争自由基(氧化还原)途径进行彻底的动力学分析而设计的。我们强调了这种脱烯基炔基化通过复杂分子(包括天然产物和药物)的多次合成后转化和后期多样化的潜力。
Regio‐ and stereoselective addition of a silyl‐substituted alkynyl sulfide to various terminal alkynes proceeds in the presence of a palladium catalyst to give (Z)‐1‐thio‐1,3‐enynes, which are useful building blocks for the synthesis of polysubstituted 1,3‐enynes. Addition to internal alkynes also takes place under solvent‐free conditions (see scheme).
Unusual two-bond13C,13C coupling constants in sulphones
作者:Christoph Rücker、Hans Fritz
DOI:10.1002/mrc.1260261213
日期:1988.12
structurally diverse sulphones. In open‐chain (single coupling path) sulphones this 2J coupling ranges from 5.5 to 27.2 Hz, while in cyclic (multiple coupling path) sulphones values ranging from 4.3 to 21.6 Hz are observed. Sulphides and sulphoxides do not exhibit a corresponding coupling of comparable magnitude. A positive sign for this coupling is derivedfrom the data of cyclic sulphones. Whereas substituents
Photochemical Functionalization of Heterocycles with EBX Reagents: C−H Alkynylation versus Deconstructive Ring Cleavage**
作者:Errika Voutyritsa、Marion Garreau、Maroula G. Kokotou、Ierasia Triandafillidi、Jérôme Waser、Christoforos G. Kokotos
DOI:10.1002/chem.202002868
日期:2020.11.11
The development of novel methodologies for the functionalization of saturated heterocycles is highly desirable. Herein, we report a cheap and efficient photochemical method for the C−H functionalization of saturated O‐heterocycles, as well as the deconstructive ring‐cleavage of S‐heterocycles, employing hypervalent iodine alkynylation reagents (ethynylbenziodoxolones, EBX). This photochemical alkynylation
medicinal chemistry. We herein disclose an efficient and practical preparation of sulfonyl alkynyl/allyl/cyano-substituted BCP derivatives through a novel radical-mediated difunctionalization of propellane. The radical alkynylation, allylation, and cyanation processes readily proceed under mild photochemical conditions. The synthetic method features broad functional group tolerance, high product diversity
Regiodivergent Rhodium(I)-Catalyzed Azide–Alkyne Cycloaddition (RhAAC) To Access Either Fully Substituted Sulfonyl-1,2,3-triazoles under Mild Conditions
A regiodivergent Rh(I)-catalyzed azide–alkynecycloaddition (RhAAC) was developed for the synthesis of both fully substituted 4-sulfonyl-1,2,3-triazoles and 5-sulfonyl-1,2,3-triazoles in high regioselectivities and yields undermildconditions in one step. Nonmetallic sulfur(II) or sulfur(VI) could efficiently control the regioselectivity of RhAAC reactions by chelation or nonchelation mechanisms to