73839-46-0Relevant articles and documents
Favorskii-Type Rearrangement of α,α'-Dihalo Ketones Induced by Enolates of (Diethoxyphosphynyl)acetic Esters and Its Application to the Synthesis of α,α'-Divinyl Ketones
Sakai, Takashi,Amano, Eiichiro,Miyata, Kazuyoshi,Utaka, Masanori,Takeda, Akira
, p. 1945 - 1947 (1987)
A Favorskii-type rearrangement of 1,3-dihalo-3-methyl-2-butanone with enolate of ethyl (diethoxyphosphinyl)acetate or t-butyl (diethoxyphosphinyl)acetate gave ethyl 2-(diethoxyphosphinyl)-5-methyl-3-oxo-4-hexenoate(3a) or its t-butyl ester (3b).Compound 3b was applied to the preparation of (E)-5-methyl-1-(p-tolyl)-1,4-hexadien-3-one and diethyl (4-methyl-2-oxo-3-pentenyl)phosphonate, which are the important intermediates for natural product syntheses.
Silanes in Organic Synthesis. 8. Preparation of Vinylsilanes from Ketones and Their Regiospecific Cyclopentenone Annulation
Paquette, Leo A.,Fristad, William E.,Dime, David S.,Bailey, Thomas R.
, p. 3017 - 3028 (2007/10/02)
A general method is described for the formation of vinylsilanes from ketones.Thus, conversion to the benzene- or p-toluenesulfonylhydrazone and sequential treatment with n-butyllithium and chlorotrimethylsilane in anhydrous tetramethylethylenediamine proceeds regiospecifically to afford the less substituted vinylsilane (in unsymmetrical cases).Friedel-Crafts acylation with acryloyl chlorides and aluminium chloride and subsequent Nazarov cyclization with Lewis acid catalysis results in cyclopentenone annulation.Numerous examples that reveal the scope of this processare described.Due to accompanying polymerization, annulation with acryloyl chloride itself is least efficient.This complication can, however, be averted through use of β-chloropropionyl chloride and dehydrochlorination with 1,5-diazabicycloundec-5-ene prior to ring closure.
