ortho-Acetoxylation of Phosphonic and Phosphoric Monoacids via Pd(II) Catalysis

Abstract

A simple and efficient method is developed for Pd-catalyzed ortho-acetoxylation using organophosphates, namely, benzylic phosphonic and aryl phosphoric monoacids, as the directing group.

Transition‐Metal‐Catalyzed Acyloxylation: Activation of C(sp2)–H and C(sp3)–H Bonds

“…C–H bond activation in arylphosphonic and ‐phosphoric acids and methyl hydrogen phenylphosphonate (compounds 93 ) proceeded through the formation of six‐membered palladacycles, in the presence of Pd(OAc) 2 in the 5–10 mol‐% range and 2–3 equiv. PhI(OAc) 2 . The temperature was found to have an important impact on the reaction yield, showing the sensitive character of reactants toward the thermal conditions (Scheme ).…”

“…PhI(OAc) 2 . [59] The temperature was found to have an important impact on the reaction yield, showing the sensitive character of reactants toward the thermal conditions (Scheme 30). Scheme 30.…”

Ruthenium(II)-catalyzed <I>Ortho</I> C-O Bond formation of Substituted Aromatics with Oxygen Nucleophiles through C-H Bond Activation

“…Several directing groups such as 2-pyridyl, carbonyl, ester, nitrile, carboxylic acid, N-acetyl and amide can be efficiently used for the reaction. With the assistance of these directing groups, acetoxylation (Henry, 1971;Yoneyama and Crabtree, 1996;Sanford et al, 2004;Yu et al, 2005;Yu et al, 2006;Corey et al, 2006;Wu et al, 2008;Chen et al, 2009;Cheng et al, 2010;Yu et al, 2010;Yu et al, 2011;Sanford et al, 2012;Kim et al, 2013), alkoxylation (Sanford et al, 2006;Wang and Yuan, 2010), hydroxylation (Yu et al, 2009;Dong et al, 2012) and benzoxylation (Sanford et al, 2005;Cheng et al, 2011) at the ortho C-H bond of directing group substituted aromatics with various oxygen nucleophiles have been studied. Palladium and copper complexes are efficient catalysts for this type of reaction.…”

Rhodium‐Catalyzed Oxidative C–H Activation/Cyclization for the Synthesis of Phosphaisocoumarins and Phosphorous 2‐Pyrones

“…[2] Given the prevalence of phosphorus compounds in medicinal chemistry and pharmaceutical industries, [3] both the design of new structures of phosphorus compounds and their applications have been explored. Recently, Kim and our group disclosed various transitionmetal-catalyzed C À H functionalizations by using phosphoryl-related compounds as a directing group [4] in an effort to pioneer a new direct synthetic method for introducing structural variation into phosphorous compounds. [5] Moreover, by understanding the unique properties of phosphorous functional groups based on several references to the ortho-metalation of aryl-phosphoryl moieties, [6] a novel protocol for the C À H alkenylation of monophosphoric acid and benzylic phosphonic monoesters was developed.…”