Synthesis of methyl 3-bromomethylbut-3-enoate and its reactions with aldehydes and tributylchlorostannane in the presence of zinc
摘要:
Methyl 3-bromomethylbut-3-enoate smoothly reacted with prenal, beta-ionylideneacetaldehyde, benzyloxyacetaldehyde, and tributylchlorostannane in the presence of zinc and aqueous ammonium chloride in tetrahydrofuran to give the corresponding delta-hydroxy-beta-methylidenecarboxylic acid esters. In the absence of ammonium chloride, satisfactory yields of the products were obtained only in the reactions with prenal and benzyloxyacetaldehyde; these reactions involved lactonization of intermediate delta-hydroxy-beta-methylidenecarboxylic acid esters, and the double carbon-carbon bond migrated to the conjugated position with the lactone carbonyl group. The condensation of beta-ionylideneacetaldehyde with methyl 3-bromomethylbut-3-enoate was successfully used to obtain isotretinoin. Initial methyl 3-bromomethylbut-3-enoate was synthesized in a good yield from readily accessible ethyl 3,3-diethoxypropionate via cyclopropanation with ethylmagnesium bromide in the presence of titanium tetra(isopropoxide), oxidation of the acetal moiety to ester, and cleavage of the cyclopropane ring in intermediate methyl (1-methylsulfonyloxycyclopropyl)acetate.
Methyl 3-bromomethyl-3-butenoate as an isopentane building block for the stereoselective preparation of (S)-4-methyl-3,6-dihydro-2H-pyran-2-carbaldehyde and (+)-faranal
作者:Iryna V. Mineyeva、Oleg G. Kulinkovich
DOI:10.1016/j.tetlet.2010.01.120
日期:2010.4
(S)-4-Methyl-3,6-dihydro-2H-pyran-2-carbaldehyde (3), the common intermediate in the syntheses of the C17-C27 subunit of laulimalide (4) and (+)-faranal (5), the trail pheromone of the pharaoh ant, Monomorium pharaonis, were obtained via transformation of methyl 3-bromomethyl-3-butenoate (1) into allylstannane 2 and subsequent allylation of (benzyloxy)acetaldehyde (6) in accordance with the Keck procedure as the key steps. (C) 2010 Elsevier Ltd. All rights reserved.
Cyclopropane intermediates in the synthesis of chiral alcohols with methyl-branched carbon skeleton. Application in the synthesis of insect pheromones
作者:V. N. Kovalenko、I. V. Mineeva
DOI:10.1134/s1070428014070033
日期:2014.7
Synthesis of (2S)-4-Methyl- and (2S)-4-Methyl-6-oxo-3,6-dihydro-2H-pyran-2-carbaldehydes as Precursors to C22–C27 Fragments of Fijianolides and Their Synthetic Analogs
作者:I. V. Mineeva
DOI:10.1134/s1070428018090130
日期:2018.9
New schemes of synthesis of (2S)-4-methyl- and (2S)-4-methyl-6-oxo-3,6-dihydro-2H-pyran-2-carbaldehydes have been developed with the goal of obtaining C-22-C-27 fragments of fijianolides and their synthetic analogs on the basis of transformations of cyclopropanol intermediates. The C-22-C-27 block of fijianolides A and B has been synthesized.
New approach to the synthesis of macrocyclic core of cytotoxic lactone (+)-neopeltolide. Synthesis of C7–C14 segment basing on cyclopropanol intermediates
作者:I. V. Mineeva
DOI:10.1134/s1070428015080023
日期:2015.8
A new retrosynthetic procedure was developed for the synthesis of the macrocyclic core of a cytotoxic lactone (+)-neopeltolide utilizing cyclopropanol intermediates. The synthesis was suggested and carried out of the C-7-C-16 segment of (+)-neopeltolide to obtain (4S,6S)-6-[(2S)-2-hydroxypentyl]-4-methyltetrahydro-2H-pyran-2-one. The possibility was demonstrated of a formal synthesis based on the obtained product of the potential antitumor pharmaceutical (+)-neopeltolide.