Microwave-Assisted Efficient Synthesis of 2-Hydroxydeoxybenzoins from the Alkali Degradation of Readily Prepared 3-Aryl-4-hydroxycoumarins in Water

Abstract

This paper describes an operationally simple, green and efficient approach for the synthesis of 2-hydroxydeoxybenzoins bearing diverse substituents from the microwave-assisted alkali degradation of 3-aryl-4-hydroxycoumarins in water. The latter compounds were readily prepared from the intramolecular Claisen condensation reaction of methyl 2-(2-arylacetoxy)benzoates in the presence of Cs2CO3-acetone, in excellent yields and without laborious workup procedures. This method is highly atom-economic and thus applicable for the large-scale synthesis of 2-hydroxydeoxybenzoins.

Regioselective Chlorination and Suzuki–Miyaura Cross‐Coupling of 4‐Alkoxycoumarins, 4‐Alkoxy‐2‐pyrones, and Related Heterocycles

“…Thus, arylated coumarin 5a was converted into hydroxy compound 13 in 51 % yield by treatment with trimethylsilyl iodide (TMSI, formed in situ from TMSCl and NaI) followed by an acidic workup. It is noteworthy that previous routes to compounds such as 13 required cyclization of the appropriate diester or reactions of diaryliodonium salts or hazardous diazo compounds . We believe that the present conditions represent the best route to a variety of substrates in this class of compounds (Scheme ).…”

3-Phenylcoumarins as a Privileged Scaffold in Medicinal Chemistry: The Landmarks of the Past Decade

“…This is an intermolecular cycloaddition reaction with the cleavage of two independent C-CN and C-CO bonds in an unusual mechanism (Figure 6A) [55]. 3-Arylcoumarins have also been readily prepared trough an intramolecular Claisen condensation reaction of methyl 2-(2-arylacetoxy)benzoates in the presence of cesium carbonate (Cs 2 CO 3 )-acetone, in excellent yields, and with easy workup procedures (Figure 6B) [56]. Aryl-3-bromoacrylates can be cyclized into 3-arylcoumarins by microwave irradiation in DMF, in the presence of K 2 CO 3 , up to a 72% yield.…”

“…Through a simple, green and efficient approach, the synthesis of 2-hydroxydeoxybenzoins, from the microwave-assisted alkali degradation of 3-aryl-4hydroxycoumarins in water, has been reported. A wide variety of cyclization reactions can occur from this intermediate (Figure 10B) [56]. A general and efficient one-pot methodology using highly substituted 2-naphthols has been performed, exploring the dual nature of lithium bases, consisting of consecutive ring opening of available coumarins with either lithium diethylamide (LiNEt 2 ) or lithium diisopropylamide (LiNiPr 2 ) into Z-cinnamamides.…”

Overexpression of Global Regulator SCrp Leads to the Discovery of New Angucyclines in Streptomyces sp. XS-16

“…XS-16 was obtained from marine sediment samples, collected from the sea around Naozhou Island in Zhanjiang, Guangdong Province. Genomic sequencing and analysis revealed a 7.54 Mb genome for the strain XS-16; however, we only obtained two previously described compounds named flazaine [23] and 1-(2-hydroxyphenyl)-2-phenylethanone [24] under laboratory cultivation. Thus, in order to tap into the metabolic potential and obtain diversified secondary metabolites, we overexpressed SCrp, the native global regulatory factor of Crp discovered by genome mining from XS-16.…”