A Direct Synthesis of Allenes by a Traceless Petasis Reaction
作者:Devon A. Mundal、Kelly E. Lutz、Regan J. Thomson
DOI:10.1021/ja301489n
日期:2012.4.4
A one-pot synthesis of allenes by the 2-nitrobenzenesulfonylhydrazide-mediated coupling of hydroxyaldehydes or ketones with alkynyl trifluoroborate salts is reported. This mild process involves in situ formation of a sulfonylhydrazone that reacts with alkynyl trifluoroborates to generate a transient propargylic hydrazide species. Decomposition of this unstable hydrazide via an intermediate monoalkyldiazine
Vinyl-substituted (Z)-stilbenes are stereoselectively synthesised on treatment of 4-arylbuta-2,3-dien-1-ols with arylboronic acids in the presence of a rhodium(I) catalyst. The reaction proceeds through the regioselective addition of organorhodium(I) species across the aryl-substituted carbon–carbon double bond of the allene moiety and subsequent δ-elimination of Rh(I)–OH.
Defluorinative 1,3‐Dienylation of Fluoroalkyl <i>N</i>‐Triftosylhydrazones with Homoallenols
作者:Xiaolong Zhang、Jiahua Deng、Yong Ji、Rong Li、Paramasivam Sivaguru、Qingmin Song、Swastik Karmakar、Xihe Bi
DOI:10.1002/chem.202302562
日期:2023.12
Defluorinative 1,3-dienylation: A carbene strategy for the defluorinative 1,3-dienylation of fluoroalkyl N-triftosylhydrazones is reported. This method allowed for the preparation of α-fluoro-β-vinyl allyl ketones in high yield with excellent functional group tolerance.
to manzacidins A and D, here we report a highly efficient catalyticasymmetric α-allenylic alkylation reaction of NH2-unprotected aminoacid esters that is promoted by combined chiral aldehyde/palladium catalysis. Fifty examples of unnatural α,α-disubstituted aminoacid esters are reported with good-to-excellent yields and stereoselectivities. Based on this methodology, a key intermediate leading to