A Sequential Acyl Thiol–Ene and Thiolactonization Approach for the Synthesis of δ-Thiolactones
作者:Ruairí O. McCourt、Eoin M. Scanlan
DOI:10.1021/acs.orglett.9b01271
日期:2019.5.3
A novel strategy for the synthesis of δ-thiolactones from inexpensive and readily available γ-unsaturated esters has been developed. This strategy incorporates a radical acyl thiol–ene reaction as the key C–S bond forming step. Cyclization is achieved via a Steglich-type thiolactonization of 5-mercaptopentanoic acids. We report the facile and scalable synthesis of δ-thiolactones in moderate to good
The use of microwaveheatingtechnique for the acceleration of ortho ester Claisen rearrangement (a three step transformation) is described. Irradiation of a DMF solution of the allyl alcohol , triethyl orthoacetate and propionic acid (catalytic) in an Erlenmeyer flask for 10 minutes in a microwave oven generated the ester in 83% yield. Analogously, ortho ester Claisen rearrangement of a variety of
[reaction: see text]. Upon treatment with n-BuLi at low temperatures, a variety of allyl 1,1-dichlorovinyl ethers 2 undergo rearrangement to furnish gamma,delta-unsaturated esters 3 after alcohol addition. Compounds containing quaternary centers (3e: R1 = H, R2, R3 = -(CH2)5-; 3f: R1 = H, R2 = CH3, R3 = (CH2)2CH(CH3)2) may be formed in high yield and under mild conditions utilizing this protocol. The
On theClaisen Rearrangement of Allyl Ethyl Ketene Acetals Generatedin situ via Benzeneselenenic Acid Eliminiation
作者:Rita Pitteloud、Martin Petrzilka
DOI:10.1002/hlca.19790620445
日期:1979.6.8
alcohols 5, undergo benzeneselenenic acid elimination to transient ketene acetals 8 which afford γ, δ-unsaturated esters 9via the ester Claisenrearrangement (Scheme 2). Under the same conditions selenoxide 7h derived from benzyl alcohol 5h is converted back to benzyl alcohol with the concomitant formation of ethylphenylselenoacetate 12.
Synthesis and biological activity of permethrinic acid analogs containing various substituents in position 2 of the cyclopropane ring
作者:N. S. Mirzabekova、N. E. Kuz’mina、O. I. Lukashov、N. A. Sokolova、S. N. Golosov、P. V. Kazakov、T. G. Perlova、V. V. Potapova、V. A. Kheinman、G. B. Ivanova
DOI:10.1134/s107042800808006x
日期:2008.8
A number of permethrinic acid ethyl ester derivatives having various substituents [Et, Pr, Ph, Ph(CH2)n (n = 1, 2), etc.] in position 2 of the cyclopropane ring were synthesized, and their insecticidal acivity against typhoid flies., rice weevils, and bean aphides, as well as juvenoid activity on flour beetle chrysalises, was studied. The newly synthesized Compounds turned out to exhibit weak insecticidal activity against standard insects but pronounced juvenile hormone activity, which differentiates them from permethrinic acid esters.