Chiral 2,6-Bis(oxazolinyl)pyridine−Rare Earth Metal Complexes as Catalysts for Highly Enantioselective 1,3-Dipolar Cycloaddition Reactions of 2-Benzopyrylium-4-olates
enantioselectivity were obtained in 1,3-dipolar cycloadditions of 2-benzopyrylium-4-olate generated from the Rh2(OAc)4-catalyzed decomposition of o-methoxycarbonyl-α-diazoacetophenone. This reaction utilized chiral 2,6-bis(oxazolinyl)pyridine (Pybox)−rare earth metal triflate complexes as chiral Lewis acid catalysts. The reactions with several benzyloxyacetaldehyde derivatives catalyzed by a Sc(III)−Pybox-i-Pr
Formation of 1,3-Oxathiole-2-thione and 1,2,4-Trithiolane Derivatives by the Catalytic Reaction of α-Diazocarbonyl Compounds with Carbon Disulfide
作者:Toshikazu Ibata、Hirofumi Nakano
DOI:10.1246/bcsj.63.3096
日期:1990.11
The rhodium(II) acetate-catalyzed decomposition of α-diazocarbonyl compounds such as substituted α-diazoacetophenones, cyclic diazoketones, cyclic diazodiketones, and α-diazo-β-ketoesters in carbon disulfide gave 1,3-oxathiole-2-thione derivatives in good yields. Diazomalonates also gave alkyl 5-alkoxy-2-thioxo-1,3-oxathiole-4-carboxylates together with 3,5-bis[bis(alkoxycarbonyl)methylene]-1,2,4-trithiolanes
α-重氮羰基化合物如取代的 α-重氮苯乙酮、环状重氮酮、环状重氮二酮和 α-重氮-β-酮酯在二硫化碳中的乙酸铑 (II) 催化分解得到 1,3-oxathiole-2-thone 衍生物良好的收益。重氮丙二酸酯还与 3,5-双[双(烷氧基羰基)亚甲基]-1,2,4-三硫杂环戊烷一起得到烷基 5-烷氧基-2-硫代-1,3-oxathiole-4-carboxylates。1,3-oxathiole-2-thiones 的形成可以通过含有乙酸铑 (II) 的两性离子中间体的中介作用来解释,该中间体是通过二硫化碳与重氮羰基化合物催化分解中产生的酮类卡宾反应形成的。
Formation and Molecular Structure of the 2 : 1-Adducts of 1-Alkoxy-2-benzopyrylium-4-olates with Carbon Disulfide
作者:Hirofumi Nakano、Hatsue Tamura、Toshikazu Ibata
DOI:10.1246/bcsj.64.771
日期:1991.3
presence of carbondisulfide gave two 2 : 1-adducts of the intermediate 1-alkoxy-2-benzopyrylium-4-olates with carbondisulfide together with a small amount of 5-(o-alkoxycarbonylphenyl)-1,3-oxathiole-2-thiones. The intramolecular carbene-carbonyl reaction of the carbenoid generated by the decomposition of the diazo ketones was clarified to be much faster than the intermolecular attack on carbon disulfide
在二硫化碳存在下,Rh2(OAc)4 催化邻-(重氮乙酰基)苯甲酸烷基酯的分解得到中间体 1-烷氧基-2-苯并吡喃-4-醇酸盐与二硫化碳的两种 2:1-加合物以及少量 5-(o-alkoxycarbonylphenyl)-1,3-oxathiole-2-thiones。由重氮酮分解产生的类卡宾的分子内卡宾 - 羰基反应被澄清比分子间对二硫化碳的攻击要快得多。1-甲氧基-2-苯并pyrylium-4-olate 与二硫化碳的主要 2:1-加合物的分子结构通过 X 射线晶体学测定。加合物的晶体为三斜晶系,空间群为 P\bar1,晶胞尺寸为 a=12.213(1), b=11.846(1), c=7.0403(2) A, α=93.395(6) , β=102.147(5), γ=109.536(7)°,Z=2。对于 2597 次观察到的反射,最终的 R 值为 0.044。结构被确认为(S-endo,S'-endo)。
IBATA, TOSHIKAZU;NAKANO, HIROFUMI, CHEM. EXPRESS. , 4,(1989) N, C. 93-96