Synthese von Alkinen aus Enolestern

Craig, J. Cymerman; Bergenthal, M. D.; Fleming, Ian; Harley-Mason, John

doi:10.1002/ange.19690811202

Cited by 3 publications

(2 citation statements)

References 32 publications

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“…To a cooled solution (-78 °C) of 3.3 mmol of LDA in 10 mL of dry THF was added dropwise 924 mg (2192 mmol) of diethyl a-[ (trimethylsilyl) oxy] benzylphosphonate (3). The mixture was stirred for 0.5 h and then 466 mg (3.3 mmol) of benzoyl chloride was added at -78 °C.…”

Section: Diethyl A-[(trimethylsilyl)oxy]benzylphosphonate (1)mentioning

confidence: 99%

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Silyl phosphites. 16. Mechanism of the Perkow reaction and the Kukhtin-Ramirez reaction. Elucidation by means of a new type of phosphoryl rearrangements utilizing silyl phosphites

Sekine¹,

Nakajima²,

Hata³

1981

J. Org. Chem.

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Reactions of -lithiated diethyl a-[(trimethylsilyl)oxy]benzylphosphonate (4) with benzoyl chloride and chloroiodomethane afforded benzoylated and chloromethylated products (1 and 2) corresponding to the 1:1 carbonyl adducts of diethyl trimethylsilyl phosphite with benzil and phenacyl chloride which were not obtained by the reactions between the phosphite and benzil or phenacyl chloride. Pyrolysis of 1 and 2 afforded 1,3,2-dioxaphosphole (6) and enol phosphate (8). On the other hand, treatment of 1 and 2 with tetrabutylammonium fluoride afforded benzoin phosphate (7) and 1,2-epoxy phosphonate (14), respectively, as the main products. These results are also discussed in connection with the mechanism of the Perkow reaction and the Kukhtin-Ramirez reaction.

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Section: Diethyl A-[(trimethylsilyl)oxy]benzylphosphonate (1)mentioning

confidence: 99%

“…In this paper, we report thermal or fluoride ion promoted phosphoryl rearrangements of diethyl a-benzoyl-a-[(trimethylsilyl) oxy] benzylphosphonate (1) and diethyl a-(chloromethyl)-a-[(trimethylsilyl)oxy]benzylphosphonate (2), which were easily obtained from diethyl a-[(trimethylsilyl)oxy]benzylphosphonate (3).…”

mentioning

confidence: 99%

Silyl phosphites. 16. Mechanism of the Perkow reaction and the Kukhtin-Ramirez reaction. Elucidation by means of a new type of phosphoryl rearrangements utilizing silyl phosphites

Sekine¹,

Nakajima²,

Hata³

1981

J. Org. Chem.

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Semicyclic 3‐Trifloxypropen‐ and Propyniminium Triflates

et al. 1994

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0-Sulfonylation of 2-oxomethylene-substituted 1-azaheterocycles 1 yields the 3-trifloxypropeniminium triflates 2a-e in high yield. Thermal 0-elimination of triflic acid from these salts affords the propyniminium triflates (2-ethynylcycliminium triflates) 3a-e. The treatment of semicyclic enamino ketones If, g with triflic anhydride yields directly the propyniminium triflates 3f, g. In earlierwe have shown that 3-trifloxypropeniminium salts are easily available from enamino ketones and triflic anhydride. Although the chemistry of these novel conjugated iminium systems has not yet been fully developed, some extended opportunities in synthesis in comparison with the related 3-chloropropeniminium saltsL41 have already emerged. Among the salient features of the former salts are their easy isolation [5], their enhanced propensity to undergo nucleophilic substitution at C-3r6l, and the facile p-elimination of triflic acid leading to propyniminium triflate~[*,~]. The latter systems are, among other things, valuable precursors of highly substituted and functionalized aminoallenes, 1-aminobutadienes, and 2-aminobutadienes"].So far, we have concentrated on systems with an acyclic iminium function. In a logical extension, we have decided to look into the chemistry of analogous semicyclic 3-trifloxypropeniminium and propyniminium salts, i.e. with the iminium function incorporated in a ring.In view of the synthetic opportunities mentioned, the interest in both classes as versatile building blocks is evident. Semicyclic 3-trifloxypropeniminium salts are expected to be more reactive than the related semicyclic 3-chloropropeniminium salts that have been used, inter alia, in the synthesis of polymethine dyes (for references see ref.L41) and terminal arylacetylenes [8], and in heterocyclic synthesis involving ring/chain transfer reactions [9]. A few semicyclic propyne iminium salts have already been prepared by various other routes, among them 2-alkynyl-substituted N-alkylpyridinium ['o] and N-alkylquinolinium furthermore acetylenic analogues of cyanine dyes with N-alkylquinolinium, N-alkyl-l,3-benzothiazolium, 1,3-dialkylbenzimidazolium, and related end In this paper we report on the synthesis of semicyclic 3-trifloxypropeniminium and propyniminium salts. The reaction of semicyclic enamino ketones l a -e with triflic anhydride yields the 3-trifloxypropeniminium triflates 2a-e rapidly and in high yield (Scheme 1). The presence of a covalently bound trifloxy group in these salts is indicated by a strong absorption in the 1400-1420 cm-l region of the IR spectrum, furthermore by the presence of a quartet at 6 = 117.6-119.4 in addition to the quartet for the carbon atom in the anionic triflate group (Table 1).All salts occur in only one configuration; for 2a, b, the s-trans,Z form shown in Scheme 2 is suggested by NOE experiments. This configuration is the sterically most favorable one and has also been found in related 3-chloropropeniminium ions['] (2a, b, C1 instead of OTf). The configuration of 2c could not be established unequivo...

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Eliminations to Form Alkenes, Allenes and Alkynes and Related Reactions

Krebs

Swienty-Busch

1991

Comprehensive Organic Synthesis

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Synthese von Alkinen aus Enolestern

Cited by 3 publications

References 32 publications

Silyl phosphites. 16. Mechanism of the Perkow reaction and the Kukhtin-Ramirez reaction. Elucidation by means of a new type of phosphoryl rearrangements utilizing silyl phosphites

Silyl phosphites. 16. Mechanism of the Perkow reaction and the Kukhtin-Ramirez reaction. Elucidation by means of a new type of phosphoryl rearrangements utilizing silyl phosphites

Semicyclic 3‐Trifloxypropen‐ and Propyniminium Triflates

Eliminations to Form Alkenes, Allenes and Alkynes and Related Reactions

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