Naphthalene-catalysed lithiation of 3-chloro-2-chloromethylpropene in a Barbier-type process with carbonyl compounds
摘要:
The reaction of 3-chloro-2-chloromethylpropene (1) and carbonyl compounds (2) with an excess of lithium powder in the presence of a catalytic amount of naphthalene (6%) in tetrahydrofuran at -78 to 20-degrees-C leads, after hydrolysis, to the corresponding methylenic 1,5-diols 3 in a Barbier-type process. The treatment of the crude diols 3 with 12 M hydrochloric acid affords selectively the corresponding substituted dihydropyrans 6.
New Trimethylenemethane Dianion Synthons: Application to the Preparation of Substituted Perhydrofuro[2,3-b]furans
作者:Emilio Lorenzo、Francisco Alonso、Miguel Yus
DOI:10.1016/s0040-4020(00)00060-0
日期:2000.3
The reaction of 3-chloro-2-(chloromethyl)prop-1-ene (1) with lithium powder and a catalytic amount of naphthalene in the presence of different electrophiles in THF at −78°C yields products 2. When carbonylic compounds are used as electrophiles the corresponding methylenic diols are obtained, which by tandem hydroboration–oxidation with alkaline hydrogen peroxide and treatment with PCC (for ketone derivatives)
The reaction of functionalised mono or dichlorinated materials 1a–6a with an excess of lithium and a catalytic amount of a naphthalene (PN) or biphenyl (PB) supportedpolymer (eassily prepared by radical copolymerisation of 2-vinylnaphthalene or 4-vinylbiphenyl with vinylbenzene and divinylbenzene) in THF either in the presence or not of different electrophiles [Me3SiCl, iPrCHO, PhCHO, Et2CO, (CH2)4CO
An efficient synthesis of substituted perhydrofuro[2,3-b]furans has been accomplished from readily accesible 3-methylidene-1,5-diols based on an intramolecular acetalisation under Wacker-typereaction conditions.
在Wacker型反应条件下,基于分子内缩醛化反应,由容易获得的3-亚甲基-1,5-二醇可以有效地合成取代的全氢呋喃[2,3- b ]呋喃。
Naphthalene-catalysed lithiation of 3-chloro-2-chloromethyl-propene: A barbier-type practical alternative to the trimethylenemethane dianion
作者:Diego J. Ramón、Miguel Yus
DOI:10.1016/0040-4039(92)88181-4
日期:1992.4
The reaction of equimolar amounts of 3-chloro-2-chloromethylpropene (2) and a carbonyl compound (3) with an excess of lithium powder and a catalytic amount (6%) of naphthalene in tetrahydrofuran at −78°C leads, after hydrolysis with water, to the corresponding diols 4 in a Barbier-type process.
Synthesis of Substituted 1,6-Dioxaspiro[3.4]octanes from 3-Chloro-2-(chloromethyl)prop-1-ene
作者:Francisco Alonso、Larry R. Falvello、Phillip E. Fanwick、Emilio Lorenzo、Miguel Yus
DOI:10.1055/s-2000-6289
日期:——
The naphthalene-catalysed lithiation of 3-chloro-2-(chloromethyl)prop-1-ene, in the presence of symmetrically substituted ketones, led to the corresponding methylenic homoallylic diols, which upon treatment with iodine and silver(I) oxide in dioxane/water furnished a series of 1,6-dioxaspiro[3.4]octanes. These compounds are structural units present in some natural compounds such as clementeins and subexpinnatins.