当前位置：
X-MOL 学术
›
J. Org. Chem.
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Theoretical Study of the BF3-Promoted Rearrangement of Oxiranyl N-Methyliminodiacetic Acid Boronates
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2017-05-11 00:00:00 , DOI: 10.1021/acs.joc.7b01096 Margarita M. Vallejos 1 , Silvina C. Pellegrinet 2
The Journal of Organic Chemistry ( IF 3.3 ) Pub Date : 2017-05-11 00:00:00 , DOI: 10.1021/acs.joc.7b01096 Margarita M. Vallejos 1 , Silvina C. Pellegrinet 2
Affiliation
|
The mechanism of the rearrangement of oxiranyl N-methyliminodiacetyl (MIDA) boronates in dicholoromethane has been extensively investigated with density functional theory. Several reaction pathways were examined. Our results revealed that the most-favorable mechanisms for the BF3-promoted rearrangement of 2-phenyl oxiranyl MIDA boronate (1) and 1-phenyl oxiranyl MIDA boronate (24) comprise two steps: ring opening of the epoxide to a carbocation intermediate followed by migration of a MIDA-boryl group (for the reaction of 1) and hydrogen (for the reaction of 24), to give the same BF3-coordinated α-boryl aldehyde in both cases. The first step of the ring opening of the epoxide is the rate-determining step of these reactions. In the rearrangement step for the reaction of 1, the MIDA-boryl group migrates easily, probably because of its electron-rich sp3-hybridized boron center. For 24, the most-favorable pathway involves a rare boryl-substituted carbocation. The course of these reactions is mainly controlled by electronic effects, although steric effects are also significant. The higher energy barrier calculated for the unsubstituted oxiranyl MIDA boronate (31) explains the lack of reactivity in the studied BF3-promoted rearrangement.
中文翻译：
BF 3促进O-氧烷基N-甲基亚氨基二乙酸硼酸酯重排的理论研究
密度泛函理论已广泛研究了邻苯二甲甲烷中氧代氧烷基N-甲基亚氨基二乙酰基（MIDA）硼酸酯的重排机理。研究了几种反应途径。我们的研究结果表明，BF 3促进2-苯基氧代芳基MIDA硼酸酯（1）和1-苯基氧代芳基MIDA硼酸酯（24）的最有利机制包括两个步骤：随后将环氧化物开环成碳正离子中间体通过使MIDA-硼基（对于1的反应）和氢（对于24的反应）迁移，得到相同的BF 3两种情况下均能配位的α-硼醛。环氧化物开环的第一步是这些反应的速率确定步骤。在1的反应的重排步骤中，MIDA-硼基很容易迁移，这可能是因为其富含电子的sp 3-杂化了硼中心。对于24来说，最有利的途径涉及稀有的硼基取代的碳阳离子。这些反应的过程主要受电子效应控制，尽管空间效应也很重要。计算出的未取代的氧杂芳基MIDA硼酸酯的较高能垒（31）解释了在研究的BF 3促进的重排中缺乏反应性。
更新日期：2017-05-23
中文翻译：
BF 3促进O-氧烷基N-甲基亚氨基二乙酸硼酸酯重排的理论研究
密度泛函理论已广泛研究了邻苯二甲甲烷中氧代氧烷基N-甲基亚氨基二乙酰基（MIDA）硼酸酯的重排机理。研究了几种反应途径。我们的研究结果表明，BF 3促进2-苯基氧代芳基MIDA硼酸酯（1）和1-苯基氧代芳基MIDA硼酸酯（24）的最有利机制包括两个步骤：随后将环氧化物开环成碳正离子中间体通过使MIDA-硼基（对于1的反应）和氢（对于24的反应）迁移，得到相同的BF 3两种情况下均能配位的α-硼醛。环氧化物开环的第一步是这些反应的速率确定步骤。在1的反应的重排步骤中，MIDA-硼基很容易迁移，这可能是因为其富含电子的sp 3-杂化了硼中心。对于24来说，最有利的途径涉及稀有的硼基取代的碳阳离子。这些反应的过程主要受电子效应控制，尽管空间效应也很重要。计算出的未取代的氧杂芳基MIDA硼酸酯的较高能垒（31）解释了在研究的BF 3促进的重排中缺乏反应性。
京公网安备 11010802027423号