Regiocontrolled Synthesis of Ring-Fused Thieno[2,3-c]pyrazoles through 1,3-Dipolar Cycloaddition of Nitrile Imines with Sulfur-Based Acetylenes
作者:Jay Zumbar Chandanshive、Bianca Flavia Bonini、Denis Gentili、Mariafrancesca Fochi、Luca Bernardi、Mauro Comes Franchini
DOI:10.1002/ejoc.201001048
日期:2010.11
1,3-Dipolarcycloadditions of C-carboxymethyl-N-arylnitrile imines with substituted acetylenes bearing thiol or sulfone groups were studied. The sulfur controls the regiochemistry of the reaction, and this protocol was applied to the synthesis of ring-fused thieno[2,3-c]pyrazoles.
A method for the preparation of aryl α,α-difluoroethyl thioethers (ArSCF2CH3) is reported and the synthesis approach is extended to aryl α,α-difluoroethyl oxygen ethers. Selected building blocks are further elaborated in cross-coupling reactions and are incorporated into analogues of established trifluoromethyl ether drugs. Conformations are explored and log P studies of these motifs indicate that
C-Glycosidation is of significance for introducing carbon chains to sugar nuclei from the chiral pool. Silylacetylenes have been shown to be sufficiently reactive for the selective introduction of acetylenic groups, usefull for organic synthesis.
tributylstannyl enolates derivedfrom aromatic ketones reacted with electron-deficientalkenes and a variety of alkynes to give the corresponding carbostannylated adducts. The reactions with methyl acrylate gave alpha-tributylstannylmethyl-gamma-ketoesters, unlike the known Michael-type reaction of stannyl enolates forming delta-ketoesters. The carbostannylation of alkynes proceeded in an anti addition
Iron (III)‐Promoted Synthesis of Substituted 4
<i>H</i>
‐Chalcogenochromenes and Chemoselective Functionalization
作者:Isadora M. de Oliveira、C. Henrique A. Esteves、Mariana P. Darbem、Daniel C. Pimenta、Julio Zukerman‐Schpector、Antonio G. Ferreira、Hélio A. Stefani、Flavia Manarin
DOI:10.1002/adsc.201900142
日期:2019.7.2
The iron(III)‐promoted synthesis of densely‐substituted 4H‐chalcogenchromene from organochalcogen propargylamines in the presence of diaryl dichalcogenides is reported. Subsequent C2‐functionalization with electrophiles and potassium trifluoroborate salts via Suzuki‐Miyaura coupling reaction are also presented. A plausible mechanism based on HRMS experiments is proposed and discussed.