Fused Benzo[b]fluorenols: Palladium‐Catalyzed Intramolecular Dehydroaromatization and Carbonyl Reduction

Abstract

Benzo[b]fluorenols were prepared by a new palladium-catalyzed one-pot reaction of enone-ynes with 3-bromoprop-1-yne through intramolecular dehydroaromatization and carbonyl reduction.

Base-controlled 1,6-enyne-bicyclization: divergent synthesis of benzo[b]fluorenones and benzo[b]fluorenols

“…9 Recently, Hu and co-workers synthesized substituted benzo [b]fluorenols from enone-ynes through intramolecular dehydroaromatization and carbonyl reduction, but involved the use of palladium as a metal catalyst and 3-bromoprop-1-yne as an additive (Scheme 1b). 10 Particularly, these reactions only gave benzo [b]fluorenones or benzo [b]fluorenols. In sharp contrast, a convenient and selective synthesis of benzo [b]fluorenones and benzo [b]fluorenols using same reagents in a single step is virtually unexplored.…”

Dynamic effects in the didehydro‐Diels‐Alder (DDDA) reaction of enyne‐ketoenes: 50% stepwise bond formation in spite of concerted transition state

“…We synthesized the enyne‐ketoene 1 according to the reported procedure and investigated its thermal behavior by heating it at 160°C in toluene for 1 hour. While the reaction mixture was found to be more complicated than anticipated, the expected product 2 was readily identified by a sharp singlet at 8.25 ppm (in CDCl 3 ) matching the position in the literature reported 1 H NMR of 2 .…”

“…[12] The computational investigation reveals that the transformation occurs at the concerted/stepwise boundary, so that it can only be described in proper terms by considering dynamic effects. We synthesized the enyne-ketoene 1 according to the reported procedure [13] and investigated its thermal behavior by heating it at 160°C in toluene for 1 hour. While the reaction mixture was found to be more complicated than anticipated, the expected product 2 was readily identified by a sharp singlet at 8.25 ppm (in CDCl 3 ) matching the position in the literature reported 1 H NMR [14] of 2.…”

4-(6-Benzyl-7-oxo-1,2,3,4,5,5a,5a1,6,7,7a,8,12b-dodecahydrobenzo[f]cycloocta[cd]isoindol-8-yl)benzonitrile

“…For the atom economy and environmental benefits of using a domino reaction to construct a structurally complicated molecule, see: Zhao et al (2012). For palladium-catalysed coupling reactions, see: Hu et al (2009Hu et al ( , 2010.…”

“…Domino reaction as an efficient protocol to construct structurally complicate molecule due to high atom economy and environmental benefits (Zhao et al, 2012). Palladium-catalyzed domino reactions have become an important tool of modern organic synthesis chemistry (Hu et al, 2009(Hu et al, , 2010.…”