Ring-Opening Reactions of 2-Alkoxy-3,4-dihydropyrans with Thiols or Thiophenols
作者:Minghao Li、Haoquan Li、Tao Li、Yanlong Gu
DOI:10.1021/ol103110q
日期:2011.3.4
An electrophilic ring-opening reaction of 2-alkoxy-3,4-dihydropyran with a thiophenol or thiol is developed for the first time. The generated product contains not only a 1,3-dicarbonyl moiety but also a fragment of bis(alkylthio)methane. A possible mechanism is also proposed on the basis of postulating a ring-opening monotransthioacetalization product, which was prepared by using LiBr as catalyst as
From Waste Biomass to Solid Support: Lignosulfonate as a Cost-Effective and Renewable Supporting Material for Catalysis
作者:Shaohuan Sun、Rongxian Bai、Yanlong Gu
DOI:10.1002/chem.201303364
日期:2014.1.7
2) lignin‐SO3Cu(OTf), and 3) lignin‐IL@NH2 (IL=ionic liquid). These solidmaterials were then examined in many organic transformations. It was finally found that, compared with its homogeneous counterpart as well as some other solid catalysts that are prepared by using different supports with the same metal or catalytically active species, the lignin‐supported catalysts showed better performance in these reactions
Manganese Chloride as an Efficient Catalyst for Selective Transformations of Indoles in the Presence of a Keto Carbonyl Group
作者:Minghao Li、Jie Yang、Yanlong Gu
DOI:10.1002/adsc.201100211
日期:2011.6
which the desired acid‐catalyzed reaction could be promoted and, at the same time, a side reaction that also needs assistance of acid, the electrophilic reaction of indole with the co‐existing keto carbonyl group, does not occur. Some acid‐catalyzed reactions, such as the ring‐opening reaction of 2‐alkoxy‐3,4‐dihydropyran with indole, and transesterification of β‐ketoester with an alcohol that contains
2-Alkoxy-3,4-dihydropyrans were proved to be a class of powerful modular substrates to construct polyheterocycles by reacting with NH2-containing dinucleophiles, such as anthranilamide, 2-aminobenzenethiol, 1-(2-aminophenyl)pyrrole, and 2-(o-aminophenyl)indole in the presence of LiBr·H2O. A three-component reaction of isatoic anhydride, 2-alkoxy-3,4-dihydropyran and amine was also developed as well
CuBr2, that can increase the reactivity of α-oxoketenedithioacetal was used in conjunction with a moderate Lewis acid, MnCl2·4H2O. The mechanism of synergistic catalysis was also studied with the aid of spectroscopic investigation. It was found for the first time that CuBr2-induced disintegration of a super-conjugation system exists in α-oxoketenedithioacetal and is responsible for the increase of its