Tandem rearrangement, cyclization and aromatization of sulfur bridged propargylic systems
作者:Samuel Braverman、Yossi Zafrani、Hugo E Gottlieb
DOI:10.1016/s0040-4039(00)00221-5
日期:2000.4
The reactivity of some novel pi-conjugated bis-propargylic sulfides, sulfoxides and sulfones under basic conditions has been investigated. These compounds undergo isomerization to the corresponding diallenes, followed by a tandem cyclization and aromatization of the latter via a diradical intermediate. Surprisingly, we have found that the rate of the cyclization step was independent of the nature of the bridging functionality. (C) 2000 Elsevier Science Ltd. All rights reserved.
Base catalyzed rearrangement of π-conjugated sulfur and selenium bridged propargylic systems
作者:Samuel Braverman、Yossi Zafrani、Hugo E Gottlieb
DOI:10.1016/s0040-4020(01)00923-1
日期:2001.10
A series of novel π-conjugated bis-propargylic sulfides, selenides, sulfoxides and sulfones have been prepared. In the presence of amine bases these compounds underwent facile isomerization to the corresponding allenes, followed by a tandem cyclization and aromatization of the latter via a diradical intermediate. While the reactions of sulfones and sulfoxides were almost spontaneous and proceeded in
Sequential Intermediates in the Base-Catalyzed Conversion of Bis(π-conjugated propargyl) Sulfones to 1,3-Dihydrobenzo- and Naphtho[<i>c</i>]thiophene-2,2-dioxides
作者:Yossi Zafrani、Hugo E. Gottlieb、Milon Sprecher、Samuel Braverman
DOI:10.1021/jo051692i
日期:2005.11.1
In a recent article, we reported on the base-catalyzed rearrangements of dipropargyl selenides, -sulfides, -sulfoxides, and -sulfones that eventually lead to polycyclic aromatic products. In the present work, we report on the first isolation and characterization of the thiophene dioxide intermediates 5b,c from a mild tandem isomerization/cyclization/aromatization of bis(π-conjugated propargyl) sulfones