A convergent formal [4 + 2] cycloaddition of 1,6-diynes and benzyl azides: construction of spiro-polyheterocycles
作者:Ming Bao、Wei Lu、Han Su、Lihua Qiu、Xinfang Xu
DOI:10.1039/c8ob00735g
日期:——
A convergent formal [4 + 2] cycloaddition reaction for the construction of structurally appealing spiro-tetrahydroquinolines has been developed, in which, a one-pot reaction is established for the in situ generation of two reagents, a cyclic alkyne and an N-aryliminium ion, from the corresponding precursors in the presence of an Au-catalyst and Brønsted acid, respectively.
Synthesis of Polycyclic Isoindoline Derivatives via Tandem Pd-Catalyzed Coupling, Propargyl–Allenyl Isomerization, [4 + 2] Cycloaddition and Aromatization Reaction
作者:Shugao Zhu、Jian Cao、Luling Wu、Xian Huang
DOI:10.1021/jo301437k
日期:2012.11.16
We report in this paper an interesting sequential reaction involving sequential Sonogashira coupling, propargyl–allenyl isomerization, [4 + 2] cycloaddition and aromatization reaction, which provides a facile method for the synthesis of a variety of polycyclic isoindoline derivatives from easily accessible starting materials.
A green protocol (compared to the existing methodology) for carrying out Garratt-Braverman cyclization has been developed. The method involves stirring a pre-absorbed bispropargyl sulfone/ether/sulfonamide over basic alumina. The reaction with sulfones was over within 10-15 mm at room temperature whereas for the ether/sulfonamide the reaction took 6-8 h at 130 degrees C. The products, aryl naphthalene derivatives, are obtained by simple filtration through Celite, in excellent yields. (C) 2014 Elsevier Ltd. All rights reserved.