Selective carbon-carbon bond formation via transition metal catalysis. 37. Controlled carbometalation. 16. Novel syntheses of .alpha.,.beta.-unsaturated cyclopentenones via allylzincation of alkynes
01 Oct 1983-Journal of the American Chemical Society (American Chemical Society)-Vol. 105, Iss: 22, pp 6761-6763
About: This article is published in Journal of the American Chemical Society.The article was published on 1983-10-01. It has received 112 citations till now. The article focuses on the topics: Carbometalation & Carbon–carbon bond.
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TL;DR: A critical review of the development of palladium-catalyzed carbonylative coupling reactions of aromatic halides and related compounds with carbon nucleophiles with palladium catalysts concludes that these reactions are important intermediates in the manufacture of dyes, pharmaceuticals, agrochemicals, and other industrial products.
Abstract: Palladium-catalyzed carbonylative coupling reactions of aromatic halides and related compounds have undergone a rapid development during recent years. Nowadays, a plethora of palladium catalysts are available for the synthesis of ketones, alkynones, chalcones, etc., which are important intermediates in the manufacture of dyes, pharmaceuticals, agrochemicals, and other industrial products. In this critical review, we summarize the development of these carbonylative transformations with carbon nucleophiles (136 references).
754 citations
576 citations
TL;DR: Metallo-ene reactions, hardly recognized until very recently, have experienced a breathtaking development when applied in an intramolecular sense as mentioned in this paper and have served as a cornerstone for numerous syntheses of structurally diverse natural products (e.g., sesquiterpenes of marine or plant origin, alkaloids, fragrances, insect defense compounds, and a fungitoxin).
Abstract: Metallo-ene reactions, hardly recognized until very recently, have experienced a breathtaking development when applied in an intramolecular sense. Efficient regio- and stereoselective magnesium-ene cyclizations have served as a cornerstone for numerous syntheses of structurally diverse natural products (e.g., sesquiterpenes of marine or plant origin, alkaloids, fragrances, insect defense compounds, and a fungitoxin). A brilliant example is the synthesis of the elusive odorant (+)-khusimone which outshines 20 years of work in the field of tricyclovetivane synthesis. Palladium-, platinum-, and nickel-catalyzed versions of the metallo-ene reaction are in a comparatively early stage of exploration, but, nevertheless, reveal intriguing potential. Hence an almost 100% stereospecific CO→C;Pd-→ CC chirality transfer permits simple and selective, cis- or trans-annelation processes. The mild cyclization conditions are compatible with various functional groups, such as nitrogen moieties, which offer interesting perspectives for the preparation of heterocycles (e.g., alkaloids) difficult to obtain by other methods. Carbon monoxide insertion reactions of the cyclized σ-metal intermediates were shown to afford annelated cyclopentanones and cyclopentenones with concomitant stereocontrolled formation of four carbon–carbon bonds. These and other observations, highlighted in this article, provide a platform for further extensions and applications of this powerful method in organic synthesis.
193 citations
144 citations
TL;DR: L'activation chimique ou ultrasonique aboutit a augmentation des rendements and a reduction des temps de formation des organozinciques and ameliore leur reactivite dans diverses reactions as mentioned in this paper.
121 citations