92545-50-1Relevant academic research and scientific papers
Highly site-selective direct C-H bond functionalization of phenols with α-aryl-α-diazoacetates and diazooxindoles via gold catalysis
Yu, Zhunzhun,Ma, Ben,Chen, Mingjin,Wu, Hai-Hong,Liu, Lu,Zhang, Junliang
supporting information, p. 6904 - 6907 (2014/06/09)
An unprecedented direct C-H bond functionalization of unprotected phenols with α-aryl α-diazoacetates and diazooxindoles was developed. A tris(2,4-di-tert-butylphenyl) phosphite derived gold complex promoted the highly chemoselective and site-selective C-H bond functionalization of phenols and N-acylanilines with gold-carbene generated from the decomposition of diazo compounds, furnishing the corresponding products in moderate to excellent yields at rt. The salient features of this reaction include readily available starting materials, unprecedented C-H functionalization rather than X-H insertion, good substrate scope, mild conditions, high efficiency, and ease in further transformation. To the best of our knowledge, this is the first example of C-H functionalization of unprotected phenols with diazo compounds.
Photochemical and Thermal Transformations of 2(3H)-Furanones and Bis(benzofuranones). A Laser Flash Photolysis study
Lohray, B. B.,Kumar, C. V.,Das, P. K.,George, M. V.
, p. 7352 - 7359 (2007/10/02)
Transformations of the 2(3H)-furanones 1-4 and bis(benzofuranones) 16-18 under steady-state photolysis and thermolysis are reported.Irradiation of 1 in benzene gives a mixture of the decarbonylated product 5 (62percent) and the cyclized phenanthrene derivative 10 (15percent).Similar results were obtained when the photolysis of 1 was carried out in methanol and acetone.Irradiation of 2 in benzene and methanol gave exclusively the decarbonylation product 6, whereas, in acetone, a mixture of the rearranged lactone 13 and and its cyclized product, 15, was obtained.Irradiation of both 3 and 4 gave the cyclized products 11 and 12, respectively.In contrast, the photolysis of the bis(benzofuranone) 16 in cyclohexane gave 3-phenylbenzo-2-(3H)-furanone (25), whereas the photolysis in methanol led to a mixture of methyl α-(2-hydroxyphenyl)phenylacetate (34) and 3-hydroxy-3-phenylbenzo-2(3H)-furanone (31).Similar results were obtained in the irradiation of 17 and 18.Neat thermolysis of furanones 1-3 at 350-450 deg C gave the decarbonylated products 5, 6, and 37 in 36-80 percent yields, whereas furanone 4 underwent facile isomerization to 5-benzyl-3,4,5-triphenyl-2(5H)-furanone (38), upon refluxing in diphenyl ether (ca. 255 deg C).Heating of bis(benzofuranones) 16-18 in refluxing cumene (ca. 150 deg C) gave the corresponding furanones 25-27 in 62-68 percent yields.Laser flash photolysis of furanones 1-4 at 248 and 337 nm leads to absorption spectral changes that can be explained in terms of singlet-mediated decarbonylation (φ = 0.3 for 2 in methanol, λex = 248 nm) and cyclization, i.e., dihydrophenanthrene formation (φ = 0.1-0.5 for 1, 3, and 4 in benzene and methanol, λex = 337 nm).The triplets of the furanones generated under energy-transfer sensitization by benzophenone in benzene are relatively long lived (r = 1.2-12 μs) and exhibit absorption maxima at 330-370 nm (εmax = (11-14) * 103 M-1 cm-1); these spectral and kinetic features appear to be characteristic of the styrene and cis-stilbene chromophores, constrained into planar configurations.Upon laser flash photolysis at 248 nm in methanol, bis(benzofuranones) 16-18 undergo facile fragmentation to the corresponding radicals 19-21, characterized by sharp and intense absorption maxima at ca. 330 nm, in addition to broad and weak absorption band systems at 500-600 nm; these radical species are the primary intermediates implicated in the formation of various final products in the course of steady-state photolysis of 16-18 under different conditions.
