Phosphororganische Verbindungen, XVII Reaktionen mit Triphenylphosphin‐dihalogeniden Über den Reaktionsverlauf der Halogenübertragung und Wasserabspaltung mit Phosphorhalogeniden

Abstract

Unter Verwendung von Triphenylphosphin–bzw. Triphenylarsin‐dihalogeiden wird für die Überführung von Alkoholen und Säuren in Alkylhalogenide bzw. Säurehalogenide der von W. Hückel vorgeschlagene Chemismus bestätigt. Für die Bildung geminaler Dihalogenide bzw. substituierter Vinylhalogenide aus Carbonylverbindungen sowie für die Dehydratisierung von Säureamiden und Oximen zu Nitrilen werden Reaktionsfolgen diskutiert, an deren Anfang die koordinative Verknüpfung der Carbonylgruppe mit dem Phosphor steht.

Synthesis of functionalized bicyclo[3.2.1]octa-2,6-dienes by thermal rearrangement of substituted 6-exo-(1-alkenyl)bicyclo[3.1.0]hex-2-ene systems

“…The combined organic extract was washed once with 1 N hydrochloric acid and three times with brine and then was dried (MgS04). Removal of the solvent, followed by distillation (air-bath temperature 81-85"C/0.1 Torr) of the residual oil, gave the desired product 18 Methyl (E)-6-rnethyl-3-0~0-6,8-nonadienoate (20) This substance was prepared via a procedure very similar to that described above (preparation of 18). From 712 p,L (6.6 mmol) of methyl acetoacetate and 1.06 g (6.6 mmol) of the bromide 16 there was obtained a crude product that was subjected to flash column chromatography (silica gel, elution with 1:4 ether -petroleum ether).…”

Reactions of tris(2-pyridyl)phosphines and tris(2-pyridyl)phosphine oxides with some electrophiles

“…It is known that triphenylphosphine dihalides react with alcohol to afford the corresponding haloalkane and triphenylphosphine oxide by the Arbusov reaction [3]. The poor yields of 4e and 5e in the reaction of 1e may be due to the occurrence of a similar Arbusov reaction.…”

Triphenylphosphine Dibromide

“…Triphenylphosphine dibromide (TPPDB, PPh 3 Br 2 ), originally synthesized by Horner and his co-workers, 1 has shown significant synthetic versatility over the course of the last decades in organic synthesis. It has been used extensively in various organic transformations, such as bromination of alcohols, phenols, and enols, cleavage of ethers and acetals to alkyl bromides, cyclization of b-and g-amino alcohols to aziridines and azetidines, conversion of carboxylic acid derivatives into acyl bromides, bromination or dehydration of carboxamide groups and epoxide opening to vicinal dibromides.…”