Pd-Catalyzed Highly Regio- and Stereoselective Formation of C–C Double Bonds: An Efficient Method for the Synthesis of Benzofuran-, Dihydrobenzofuran-, and Indoline-Containing Alkenes
A highly regio- and stereoselective C–C double bond formation reactionvia Pd-catalyzed Heck-type cascade process with N-tosylhydrazones has been developed. Various N-tosylhydrazones derived from both ketones and aldehydes are found to be efficient substrates to provide di- and trisubstitutedolefins with high regio- and stereoselectivity. Furthermore, this reaction has a good functional group tolerance
situ from tosylhydrazones. In addition, by using chiral dirhodium catalysts, we also achieved an asymmetric version of the reaction with good to excellent enantioselectivities (up to 98:2 e.r.). This is the first enantioselective heteroatom-hydrogen bond insertion reaction to use unstabilized diazo compounds as carbene precursors. The protocol exhibited good functional group tolerance and could be carried
A base‐promoted three‐component coupling of carbon dioxide, amines, and N‐tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance
I<sub>2</sub>-Promoted [4 + 2] cycloaddition of <i>in situ</i> generated azoalkenes with enaminones: facile and efficient synthesis of 1,4-dihydropyridazines and pyridazines
作者:Jiajun Feng、Tiantong He、Yuxing Xie、Yang Yu、Jonathan B. Baell、Fei Huang
DOI:10.1039/d0ob01958e
日期:——
A facile and efficient strategy for the synthesis of 1,4-dihydropyridazines and pyridazines through I2-promoted [4 + 2] cycloaddition of in situ generated azoalkenes with enaminones has been developed. The switch in selectivity is attributed to the judicious choice of different reaction temperatures. The key features of this work include controllable and selective synthesis, good functional group tolerance
已经开发了一种通过 I 2 -促进的 [4 + 2]原位生成的偶氮烯烃与烯胺酮环加成来合成 1,4-二氢哒嗪和哒嗪的简便有效的策略。选择性的转换归因于对不同反应温度的明智选择。这项工作的主要特点包括可控和选择性合成、良好的官能团耐受性、良好的反应收率、无金属/碱基条件以及一锅法的适用性。
Regioselective Synthesis of Vinyl Halides, Vinyl Sulfones, and Alkynes: A Tandem Intermolecular Nucleophilic and Electrophilic Vinylation of Tosylhydrazones
作者:Devi Prasan Ojha、Kandikere Ramaiah Prabhu
DOI:10.1021/ol503114n
日期:2015.1.2
in tandem at the carbene center to install an electrophile and a nucleophile on the same carbon. This metal-free concept, which is unprecedented, has been illustrated by regioselectivesynthesis of a variety of vinyl halides, vinyl sulfones, and alkyne derivatives.