两种铜盐(Cu(CF 3 CO 2)2和IMesCuCl)被鉴定为是地球上丰富的,廉价的但有效的金属催化剂,与重氮丙二酸酯一起用于各种环氧化物的化学/区域选择性和立体定向脱氧反应,并具有常见的官能团耐受性(烯烃,酮,酯,对甲氧基苄基,苄基,叔丁基二甲基甲硅烷基和三异丙基甲硅烷基)。特别是,空前的区域选择性使二环氧化物首次单脱氧为烯基环氧化物。密度泛函理论的机理研究表明,脱氧是通过折叠游离的叶立德而发生的,不利于通过可能的氧杂环丁烷的环还原而产生的直观途径。
Diastereoselective Borocyclopropanation of Allylic Ethers Using a Boromethylzinc Carbenoid
作者:Guillaume Benoit、André B. Charette
DOI:10.1021/jacs.6b09090
日期:2017.2.1
borocyclopropanation of (E)- and (Z)-allylic ethers and styrene derivatives via the Simmons-Smith reaction using a novel boromethylzinc carbenoid is described. The carbenoid precursor is prepared via a 3-step sequence from inexpensive and commercially available starting materials. This methodology allows for the preparation of 1,2,3-substituted borocyclopropanes in high yields and diastereoselectivities
First Evidence for the Formation of a Geminal Dizinc Carbenoid: A Highly Stereoselective Synthesis of 1,2,3-Substituted Cyclopropanes
作者:André B. Charette、Alexandre Gagnon、Jean-François Fournier
DOI:10.1021/ja017230d
日期:2002.1.1
Significant amounts of novel gem-dizinc carbenoids (RZnCHIZnR) are formed when diethylzinc is mixed with iodoform in CH2Cl2 at 0 degrees C. This reagent was shown to be effective in the cyclopropanation of butenediol derivatives to generate a cyclopropylzinc intermediate that could be trapped with a variety of electrophiles. 1,2,3-Substitutedcyclopropane derivatives are formed with excellent diastereoselectivities
Regiochemical control of the ring opening of 1:2-epoxides by means of chelating processes. 10. Synthesis and ring opening reactions of mono- and difunctionalized cis and trans aliphatic oxirane systems
The regiochemical outcome of the ring opening of 1:2-epoxides through chelation processes assisted by metal ions, was verified in mono- and difunctionalized aliphatic oxirane systems bearing the heterofunctionality (OR) in an homoallylic and/or allylic relationship to the oxirane ring. The effect of the distance of the OR functionality from the oxirane ring and of the type of protective group on the