84540-52-3Relevant academic research and scientific papers
Synthesis of substituted benzenes and phenols by ring-closing olefin metathesis
Yoshida, Kazuhiro,Takahashi, Hidetoshi,Imamoto, Tsuneo
experimental part, p. 8246 - 8261 (2009/09/29)
New synthetic approaches to substituted aromatic compounds are reported. Ring-closing olefin metathesis (RCM)/dehydration and RCM/tautomerization are the key processes in the synthesis of substituted benzenes 3 and phenols 6, respectively. Readily accessible 1,5,7-trien-4-ols 7, which are the precursors of benzenes, were prepared from β-halo-α, β-unsaturated aldehydes 11 or β-halo-α,β-unsaturated esters 19 by utilizing reliable transformations in which cross-coupling with vinylic metal reagents 12 and allylation with allylic metal reagents 13 were employed as carbon-carbon bond forming reactions. RCM of 7, followed by dehydration, afforded a wide variety of substituted benzenes 3. In addition, RCM of 1,5,7trien-4-ones 9, which were prepared by oxidation of 7, furnished various substituted phenols 6 by automatic tautomerization.
The skeletal rearrangement of gold- and platinum-catalyzed cycloisomerization of cis-4,6-dien-1-yn-3-ols: Pinacol rearrangement and formation of bicyclo[4.1.0]heptenone and reorganized styrene derivatives
Tang, Jhih-Meng,Bhunia, Sabyasachi,Sohel, Shariar Md. Abu,Lin, Ming-Yuan,Liao, Hsin-Yi,Datta, Swarup,Das, Arindam,Liu, Rai-Shung
, p. 15677 - 15683 (2008/09/19)
With gold and platinum catalysts, cis-4,6-dien-1-yn-3-ols undergo cycloisomerizations that enable structural reorganization of cyclized products chemoselectively. The AuCl3-catalyzed cyclizations of 6-substituted cis-4,6-dien-1-yn-3-ols proceeded via a 6-exo-dig pathway to give allyl cations, which subsequently undergo a pinacol rearrangement to produce reorganized cyclopentenyl aldehyde products. Using chiral alcohol substrates, such cyclizations proceed with reasonable chirality transfer. In the PtCl 2-catalyzed cyclization of 7,7-disubstituted cis-4,6-dien-1-yn-3-ols, we obtained exclusively either bicyclo-[4.1.0]heptenones or reorganized styrene products with varied substrate structures. On the basis of the chemoselectivity/structure relationship, we propose that bicyclo[4.1.0]heptenone products result from 6-endo-dig cyclization, whereas reorganized styrene products are derived from the 5-exo-dig pathway. This proposed mechanism is supported by theoretic calculations.
