Simple and commercially available starting materials, a broad substrate scope, and excellent functional group tolerability make this strategy practical for applications. Furthermore, 1,2,3-thiadiazole synthesis was realized by using potassium thiocyanate as an odorless sulfur source.
�ber eine neuartige Synthese von ?-Ketoallenen durch Reaktion von terti�ren Acetylencarbinolen mit Vinyl�thern eine ergiebige methode zur darstellung des Pseudojonons und verwandter verbindungen
作者:G. Saucy、R. Marbet
DOI:10.1002/hlca.19670500423
日期:——
The novel acid-catalysed reaction of isopropenyl ether with tertiary acetylenic carbinols to give β-ketoallenes in high yields is described. Upon treatment with bases, these allenes readily undergo isomerization to conjugated dienones. This reaction sequence results in an economic synthesis of pseudo-ionones and pseudo-irones from dehydrolinalool and its homologs.
Cyanotrimethylsilane adds to some ⇌,β-unsaturated ketones in conjugate manner under the catalytic action of Lewis acids such as triethylaluminium, aluminiumchloride, and SnCl2. Hydrolysis of the products gives β-cyano ketones which are identical to the hydrocyanated products of the starting enones. The title silicon reagent reacts with acetals and orthoesters under the catalytic action of SnCI2 or BF3-OEt2
the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturatedaldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in
Relay Catalysis To Synthesize β-Substituted Enones: Organocatalytic Substitution of Vinylogous Esters and Amides with Organoboronates
作者:Sasha Sundstrom、Thien S. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.9b04584
日期:2020.2.21
Organocatalysis was shown to facilitate conjugate additions to vinylogousesters and amides for the first time. Subsequent elimination of a β-alcohol or amine provided π-conjugated β-substituted enones. Remarkably, nucleophile addition to the electron-rich vinylogous substrates is more rapid than classical enones, forming monosubstituted products. A doubly organocatalytic (organic diol and methyl aniline)