Über Carbonyl‐ und Cyan‐phosphonsäure‐ester. II. Mitteil.: Der Reaktionsverlauf bei der Umsetzung von Phosphiten mit Brom‐ und Chlor‐aceton

Abstract

Durch Umsetzung von Triäthylphosphit mit Bromaceton werden Phosphorsäure‐diäthylester‐isopropenylester und β‐Keto‐propan‐phosphonsäure‐diäthylester erhalten. Ersterer entsteht auch aus Natrium‐diäthylphosphit und Chloraceton sowie bei der Reaktion von Diazo‐aceton mit Diäthylphosphit. — α‐Keto‐propan‐phosphorsäure‐diäthylester wurde aus Propionsäurechlorid und Triäthylphosphit dargestellt.

Chemospecific reaction of activated acetylenic compounds with triphenylphosphine in the presence of a system containing two functional groups

“…As a result, many alternative methods for effecting syntheses of phosphorus ylides from carbonyl compounds have been developed. It is worth mentioning that although the reaction of PPh 3 with compounds containing halogen groups, such as α-bromoketones, 22 carbon tetrachloride, and hexachloroacetone, [23][24][25][26] has been reported in the literature, we have not observed products derived from nucleophilic attack of the PPh 3 at the CH 2 Br group in 2-bromoacetamide. Apparently, under the present reaction conditions the phosphonium ion 3, which is conjugated with an α,β-unsaturated ester, is formed faster than salt 4, and the compound 5 is formed in a chemospecific manner (Scheme 1).…”

“…The reaction of some α-halocarbonyl compounds such as α-bromoketones with phosphines and phosphate can take an alternative course in which phosphorus attacks halogen, with the formation, respectively, of an enolate or an enol phosphate. 22,23 Also, the nucleophilic substitution reactions by a phosphorus atom can occur at an sp 3 -carbon bearing halogen, and are most valuable for synthesis. 21 When a synthesis is being undertaken with several sensitive functional groups present in the molecule, or with several sensitive molecules, milder reagents and reaction conditions may be necessary.…”

The Chemistry and Properties of Enol Phosphates.

“…This was well demonstrated by the results in the reactions of different trialkyl phosphites with chloro-, bromo-, and iodoace tones under varying conditions (table 1), yielding mixtures of , -dialkyl 2-oxopropylphosphonates (X) and dialkyl 1-methylvinyl phosphates (XI) (226,260,344).…”

Synthesis of β‐Chloro‐α‐hydroxyphosphonates through Triethylamine‐Catalyzed Pudovik Reaction

“…However, the Pudovik reaction is largely limited to β-chloro-α-hydroxyphosphonates mainly due to the regioselectivities between the carbonyl and α-halo C atom. [15][16][17][18] As reported, at least five kinds of mixed compounds may be generated including vinyl phosphates 3, [19,20] β-chloroα-hydroxyphosphonates 4, [21,22] phosphonyl epoxides 5, [23][24][25][26] βketophosphonates 6, and β-halo enolphosphates 7 [27] because of the well-known competitive Pudovik/Arbuzov /Perkow correlated-reactions (Figure 1). To the best of our knowledge, few protocols have been achieved for practical preparation of β-chloro-α-hydroxyphosphonates from α-haloketones.…”