Abstract:The subsequent double-bond isomerization in the synthesis of dibenzocycloheptenes and their heteroaromatic analogues was investigated. In the case of biphenyls, a basic additive completely prevented an isomerization to the thermodynamic product. With electron-rich intramolecular heteroaromatic nucleophiles, the isomerization was still observed, but the kinetic product can be obtained by careful control of the reaction times in most cases. Mechanistic studies demonstrated that a slow isomerization is also possi… Show more
“…Without acidic additive a mixture of 40 and the compound bearing an exo-methylene group was obtained. 22 AgNTf 2 and HNTf 2 alone were not catalytically active in this reaction. The total synthesis was completed after two steps furnishing Reticuol in 42% yield over 6 steps (Scheme 6b).…”
In this critical review the applications of gold catalysed reactions in total synthesis during the years since our last article are reviewed. At the end of this article a literature analysis is conducted to evaluate the progress in this field.
“…Without acidic additive a mixture of 40 and the compound bearing an exo-methylene group was obtained. 22 AgNTf 2 and HNTf 2 alone were not catalytically active in this reaction. The total synthesis was completed after two steps furnishing Reticuol in 42% yield over 6 steps (Scheme 6b).…”
In this critical review the applications of gold catalysed reactions in total synthesis during the years since our last article are reviewed. At the end of this article a literature analysis is conducted to evaluate the progress in this field.
“…This result suggested that the second arylation was accelerated by the additional methoxy group located at the para -position to the reacting carbon. 26 We then examined the kinetic isotope effect (eqn (4) in Scheme 6 ). The competition reaction using N -Boc-pyrroles 9F (2.5 equiv.)…”
“…Hashmi and his co-workers proposed the synthetic pathway of dibenzocycloheptane derivatives via gold-catalyzed post-cyclization isomerization (Scheme 10). 25 The 7- exo-dig hydroarylation reaction occurred with compound 20 and 5 mol% [L 6 Au(NTf 2 )] catalyst, 5 mol% of 2,6-di- tert -butylpyridine in deuterated benzene at 80 °C for 0.5–72 h and formed the desired product 21 in 41–95% yields. Compound 20 contained a di-substituted methoxyphenyl ring and gave a good yield of 95% after 3 h. When tert -butyloxycarbonyl (Boc)-protected pyrrole or indole ring was used, the tetracyclic molecule 21 was synthesized in moderate and high amounts, respectively (71% and 98%).…”
The hydroarylation of alkynes, alkene, and, allene is a cost-effective and efficient way to incorporate unsaturated moieties into aromatic substrates. This review focuses on gold-catalyzed hydroarylation, which produces aromatic alkenes,...
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