New Aspects in Phosphorus Chemistry II

Herausgegeben:Majoral, Jean-Pierre;Mitarbeit:Balczewski, P.; Caminade, A.-M.; Heydt, H.; Ito, S.; Kee, T.P.; Majoral, J.-P.; Mikolajczyk, M.; Nixon, T.D.; Streubel, R.; Verkade, J.G.; Yoshifuji, M.

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Produktbeschreibung

Strong non-ionic bases are highly advantageous as stoichiometric reagents and as catalysts in synthetic organic chemistry owing to side reactions that f- quently occur when ionic bases such as LDA or alkali metal alkoxides are employed. A second reason that non-ionic bases are frequently more useful in these applications is that such bases are often more soluble in less polar organic solvents,particularly at low temperatures. Thirdly,non-ionic bases can provide reactive naked or tightly associated deprotonated substrate anions that are s- bilized by the relatively large,poorly solvated cations formed by the protonated base. In such cations,extensive positive charge delocalization can occur. Prior to our work on pro-azaphosphatranes of type 1 (Scheme 1),the very strong n- ionic bases utilized for organic transformations were largely confined to the nitrogenous bases shown below (Scheme 2). Scheme 1 Scheme 2 4 J. G. Verkade 2 Uses of Strong Nonionic Nitrogen Bases 2. 1 Amines One of the earliest strong non-ionic bases to make its appearance was Proton Sponge and its derivatives [1] and these systems have been reviewed [2]. More recently Proton Sponge has been used in the palladium-catalyzed arylation of 2,3-dihydrofuran [3], and it also catalyzes Knoevenagel condensations of s- strates possessing activated methylene groups [4]. Recently the synthesis of the macrocyclic tetramine below (Scheme 3) was reported [5]. The encrypted nitrogens are very basic (pK ,24.

Produktdetails

• Topics in Current Chemistry 223
• Verlag: Springer / Springer Berlin Heidelberg / Springer, Berlin
• Artikelnr. des Verlages: 978-3-642-07900-9
• Softcover reprint of hardcover 1st ed. 2003
• Seitenzahl: 276
• Erscheinungstermin: 19. Oktober 2010
• Englisch
• Abmessung: 235mm x 155mm x 16mm
• Gewicht: 429g
• ISBN-13: 9783642079009
• ISBN-10: 3642079008
• Artikelnr.: 32078089

Inhaltsangabe

P(RNCH2CH2)3N: Very Strong Non-Ionic Bases Useful in Organic Synthesis.- The Asymmetric Phospho-Aldol Reaction. Past, Present and Future.- Chemistry of Phosphanylidene Carbenoids.- Transient Nitrilium Phosphanylid Complexes - New Versatile Building Blocks in Phosphorus Chemistry.- What to do with Phosphorus in Dendrimer Chemistry.- Phosphonate Chemistry and Reagents in the Synthesis of Biologically Active and Natural Products.- The Fascinating Chemistry of 1,3,5-Triphosphinines and Valence Isomers [1].