Asymmetric 1,3-Dipolar Cycloadditions of 2-Diazocyclohexane-1,3-diones and Alkyl Diazopyruvates
作者:Paul Müller、Sabrina Chappellet
DOI:10.1002/hlca.200590071
日期:2005.5
The 1,3-dipolar cycloaddition reactions of 2-diazocyclohexane-1,3-dione (7a; Table 1) and of alkyl diazopyruvates (11a–e; Table 3) to 2,3-dihydrofuran and other enolethers have been investigated in the presence of chiral transition metal catalysts. With RhII catalysts, the cycloadditions were not enantioselective, but those catalyzed by [RuIICl2(1a)] and [RuIICl2(1b)] proceeded with enantioselectivities
已经研究了2-重氮环己烷-1,3-二酮(7a;表1)和重氮丙酮酸烷基酯(11a - e;表3)与2,3-二氢呋喃和其他烯醇醚的1,3-偶极环加成反应。手性过渡金属催化剂的存在。使用Rh II催化剂时,环加成不是对映选择性的,但是当[Ru II Cl 2(1a)]和[Ru II Cl 2(1b)]催化时,对映选择性分别高达58%ee和74%ee。重氮丙酮酸盐11被用作基底。当用[Ru(pybox)]催化剂分解时,苯基碘化鎓叶立德7c比相应的重氮前体7a(表2)以较低的产率和较差的产率产生加合物8a。这表明与相应的重氮前体相反,Ru II催化剂进行的内鎓盐分解不会导致Ru-卡宾络合物作为反应性中间体。我们的方法代表了这些类型底物的首次可重现,对映选择性的1,3-环加成。
Efficient One-Pot Synthesis of Multi-Substituted Dihydrofurans by Ruthenium(II)-Catalyzed [3+2] Cycloaddition of Cyclic or Acyclic Diazodicarbonyl Compounds with Olefins
作者:Likai Xia、Yong Rok Lee
DOI:10.1002/adsc.201300245
日期:2013.8.12
AbstractRuthenium(II)‐phosphine complexes‐catalyzed [3+2] cycloadditions were conducted to synthesize a variety of dihydrofurans by reactions of cyclic or acyclic diazodicarbonyl compounds with olefins. This method represents a direct and efficient one‐pot synthesis for multi‐substituted dihydrofurans under mild reaction conditions with an excellent regioselectivity. Furthermore, to reduce reaction times and increase yields of dihydrofurans, microwave‐assisted tris(triphenylphosphine)ruthenium(II) chloride/ 1‐butyl‐3‐methylimidazolium tetrafluoroborate Ru(PPh3)3Cl2/[Bmim]BF4}‐catalyzed reactions were also developed. The synthesized dihydrofurans can be readily converted into biologically interesting tetrahydroindoles.magnified image
A new route for the synthesis of furanoflavone and furanochalcone natural products
作者:Yong Rok Lee、Andrew T. Morehead
DOI:10.1016/0040-4020(95)98689-f
日期:1995.4
An efficient synthesis of furanoflavones and furanochalcones has been carried out starting from a dihydrobenzofuran derivative.
AgBF<sub>4</sub>/[Bmim]BF<sub>4</sub>-Catalyzed [3+2] Cycloaddition of Cyclic Diazodicarbonyl Compounds: Efficient Synthesis of 2,3-Dihydrofurans and Conversion to 3-Acylfurans
A novel and efficient method for the synthesis of 2,3-dihydrofurans bearing a variety of substituents on the dihydrofuran ring was achieved by the reaction of cyclicdiazodicarbonylcompounds with styrene and vinyl acetate. The key strategy was AgBF/[Bmim]BF-catalyzed [3+2] cycloaddition. The synthesized dihydrofurans with an acetate group were further converted to the corresponding 3-acylfurans.
SYNTHESIS OF BENZOFURAN DERIVATIVES USING MANGANESE (III) ACETATE MEDIATED ADDITION OF β-DICARBONYL COMPOUNDS TO ALKYNE AND ALKENES – A COMPARATIVE STUDY
作者:Mehmet Yilmaz、A. Tarik Pekel
DOI:10.1081/scc-100108239
日期:2001.1.1
β-Dicarbonyl compounds were easily oxidized with manganese (III) acetate in acetic acid to form the corresponding α-carboradicals, which attacked alkyne and alkenes to give furan derivatives in good yield.