O–H hydrogen bonding promotes H-atom transfer from α C–H bonds for C-alkylation of alcohols
作者:Jenna L. Jeffrey、Jack A. Terrett、David W. C. MacMillan
DOI:10.1126/science.aac8555
日期:2015.9.25
alcohols is selectively induced by using an H-bonding catalyst to bind the hydroxyl group of the alcohol. The adjacent C-H bonds now become susceptible to a reaction accelerated by another pair of catalysts. In combination, the trio of catalysts promotes C-C bond formation at the alcohol C within an array of competing sites. Science, this issue p. 1532 Hydrogen bonding confers siteselectivity in a carbon-carbon
三重奏有助于激活醇中的 CH 键酶可以通过位置良好的 H 键激活分子的特定部分来加速化学反应。杰弗里等人。在合成环境中展示氢键的力量。在这里,醇的 C 中心的反应性是通过使用 H 键催化剂来结合醇的羟基而选择性地诱导的。相邻的 CH 键现在变得容易受到另一对催化剂加速的反应的影响。组合起来,这三种催化剂促进了在一系列竞争位点内的醇 C 处形成 CC 键。科学,这个问题 p。1532 氢键在醇和烯烃之间的碳-碳键形成反应中赋予位点选择性。在存在多个潜在的氢原子供体和受体的情况下,从有机分子转移氢原子的效率和选择性通常难以控制。在这里,我们描述了一种催化活化模式的机理评估,该模式通过氢原子转移机制实现了醇与丙烯酸甲酯的高选择性光氧化还原 α-烷基化/内酯化。我们的研究表明,在烯丙基、苄基、α-C=O 和 α-醚 C-H 键存在的情况下,四正丁基磷酸铵在提高醇中 α C-H 键的选择性方面具有特
One-Pot γ-Lactonization of Homopropargyl Alcohols via Intramolecular Ketene Trapping
γ-lactonization of homopropargyl alcohols via an alkyne deprotonation/boronation/oxidation sequence has been developed. Oxidation of the generated alkynyl boronate affords the corresponding ketene intermediate, which is trapped by the adjacent hydroxy group to furnish the γ-lactone. We have optimized the conditions as well as examined the substrate scope and synthetic applications of this efficient one-pot
SmCl<sub>3</sub>-catalysed electrosynthesis of γ-butyrolactones from 3-chloroesters and carbonyl compounds
作者:Hassan Hebri、Elisabet Duñach、Jacques Périchon
DOI:10.1039/c39930000499
日期:——
Electrosynthesis of γ-butyrolactones has been achieved by the direct reductive coupling of ethyl 3-chloropropionate and a series of carbonyl compounds in the presence of a catalytic amount of SmCl3.
Compounds of the formula (I):
1
wherein X is a —(C═CH
2
)— group or a —CH(CH
3
)— group, with the proviso that when X is a —(C═CH
2
)— group, R
1
is a C
1-10
alkyl group or a C
2-10
alkenyl group and when X is a —CH(CH
3
)— group, R
1
is hydrogen, a saturated or unsaturated, linear or a branched C
1-10
alkyl group, a C
1-10
acyl group, a C
1-10
cycloalkyl group or an aryl group are useful as perfumes.
Trichlorotitanium and alkoxytitanium homoenolates. Preparation, characterization, and utilization for organic synthesis
作者:Eiichi. Nakamura、Hiroji. Oshino、Isao. Kuwajima
DOI:10.1021/ja00273a032
日期:1986.6
demi-equivalent d'alcoolate de titane (IV) sont plus reactives que I, fournissant des voies d'acces a des hydroxy-4 esters, γ-lactones et cyclopropanecarboxylates. Discussion du mecanisme de formation des homoenolates
Des eseses alcoxytitaniumgenerees par traitement de trichlorotitanio-3propionates d'alkyles (I) avec un demi-equivalent d'alcoolate de titane (IV) sont plus reactors que I, Fournissant des voies d'acces a des hydroxy-4esters, γ-内酯和环丙烷羧酸盐。同烯醇化物形成机制的讨论