A variety of a-branched alkynes can be easily assembled by a Knoevenagel type condensation of 4-unsubstituted isoxazolin-5-ones with aldehydes or ketones, followed by conjugate addition of an organometallic reagent and nitrosative cleavage of the heterocyclic ring.
3-Phenylisoxazol-5-one (2) and aromatic aldehydes were condensed to 3-phenyl-(4-arylmethylene) isoxazol-5-one (3) in the presence of Al(2)0(3)-KF without solvent under microwave irradiation.
Unusual Approach to Branched 3-Alkynylamides and to 1,5-Dihydropyrrol-2-ones
作者:Igor Dias-Jurberg、Fabien Gagosz、Samir Z. Zard
DOI:10.1021/ol902472r
日期:2010.2.5
Rare carboxamide branched alkynes such as 11a can be readily obtained by reaction of the electrophilic 4-alkylidene isoxazolinones with isocycanides followed by nitrosative cleavage of the heterocyclic ring. N-lodosuccinimide induced ring closure in the presence of a nucleophile results in the formation of new iodopyrrolinones such as 16c.
CLERICI, FRANCESCA;ERBA, EMANUELA;MORNATTI, PIERLUIGI;TRIMARCO, PASQUALIN+, CHEM. BER., 122,(1989) N, C. 295-300
Enantioselective Synthesis of Functionalized Diazaspirocycles from 4‐Benzylideneisoxazol‐5(4<i>H</i>)‐one Derivatives and Isocyanoacetate Esters
作者:Pablo Martínez‐Pardo、Adrián Laviós、Amparo Sanz‐Marco、Carlos Vila、José R. Pedro、Gonzalo Blay
DOI:10.1002/adsc.202000611
日期:2020.9.8
spirocyclic compounds bearing three contiguous stereocenters and high functionalization were obtained through a formal [3+2] cycloaddition reaction catalyzed by a cooperative system. The spiro compounds were synthesized from 4‐arylideneisoxazol‐5‐ones and isocyanoacetate esters using a bifunctional squaramide/Brønsted base organocatalyst derived from a Cinchona alkaloid and silver oxide as Lewis acid. This method