Dibenzofurans by Intramolecular Ring Closure Reactions

Abstract

German version-Angew. Chem. 86,477 (1974) [I] G. D. Appleyard and C. J M. S t i r h y , J. Chem. SOC. C 1969SOC. C , 1904 [2] J W B u f f v , P. D. How,i.s, and C. J . M. S t i r h y , J C. S. Perkin I 1973, 59 [3] J . W B r i f r~, P. D. Houes, and C . J . M. Stirling, J. C. S. Perkin I 1973, 65.

Oxygen as Oxidant in Palladium-Catalyzed Inter- and Intramolecular Coupling Reactions

“…Addition of 2,4-pentanedione reduced the amount of dimerized product, but it was still significant. [16] Furthermore, transition metal-catalyzed reactions with oxygen at high pressure are hazardous, and explosions have been reported in reactions related to aromatic coupling. [1c, 17] We would therefore like to report a procedure that uses oxygen at atmospheric pressure.…”

Pd‐Catalyzed Synthesis of Oxygen‐Containing Heterocycles

“…In addition, palladium-catalyzed synthesis of sultones involving a double C(sp 2 )-H functionalization has also been achieved by Laha and coworkers (Scheme 3.3, path c) [16]. An example of the construction of dibenzofurans by palladium-catalyzed C-H arylation was reported by Itatani in 1974 (Scheme 3.4) [17]. Compared with previous methods [18], this reaction could obviate the tedious synthetic route and is suitable for the preparation of substituted dibenzofurans with high efficiency.…”

Synthesis of Dibenzo[c,e]oxepin‐5(7H)‐ones from Benzyl Thioethers and Carboxylic Acids: Rhodium‐Catalyzed Double CH Activation Controlled by Different Directing Groups

“…[1] In biaryl synthesis,t he use of selective double C À Hb ond activation [2] usually leads to am ixture of regioisomers. To further control the regioselectivity and enhance the reactivity,anintramolecular strategy was designed and applied to construct fused rings [7,8] (Scheme 1a,s ee 2). To further control the regioselectivity and enhance the reactivity,anintramolecular strategy was designed and applied to construct fused rings [7,8] (Scheme 1a,s ee 2).…”