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Heterocumulenes heteroatom nucleophilic addition

The reverse reaction, i.e., the addition of water to the heterocumulene B with formation of carbonic acid derivatives A, is also known. With very few exceptions this reaction occurs spontaneously with catalysis by an acid or base. The hydration of a heterocumulene is a special example of an entire class of heterocumulene reactions, namely the addition of heteroatom nucleophiles H-Het3 (you have already come across such a reaction briefly in Section 6.1.1 in the context of the DCC activation of carboxylic acids). Occasionally, this addition... [Pg.339]

Fig. 8.11. Tandem reaction consisting of three single reactions mutually transforming heterocumulenes and heteroatom nucleophiles in a one-pot synthesis of an isothiocyanate (1) uncatalyzed addition reaction of heteroatom nucleophile (aniline) + heterocumulene (carbon disulfide) —> carbonic acid derivative (A) (2) heterolysis-initiated /3-elimination of the carbonic acid derivative (D) -> heterocumulene (F = phenylisothiocyanate) + heteroatom nucleophile (thiocar-bonic acid O-ethylester) (3) decomposition of a carbonic acid derivative (D) to a heterocumulene (carbon oxysulfide) and a heteroatom nucleophile (ethanol) via the zwitterion H. Fig. 8.11. Tandem reaction consisting of three single reactions mutually transforming heterocumulenes and heteroatom nucleophiles in a one-pot synthesis of an isothiocyanate (1) uncatalyzed addition reaction of heteroatom nucleophile (aniline) + heterocumulene (carbon disulfide) —> carbonic acid derivative (A) (2) heterolysis-initiated /3-elimination of the carbonic acid derivative (D) -> heterocumulene (F = phenylisothiocyanate) + heteroatom nucleophile (thiocar-bonic acid O-ethylester) (3) decomposition of a carbonic acid derivative (D) to a heterocumulene (carbon oxysulfide) and a heteroatom nucleophile (ethanol) via the zwitterion H.
Fig. 8.12. Mechanism of the uncatalyzed addition (starting top left and proceeding clockwise) and the acid-catalyzed addition (starting top left and then proceeding counterclockwise) of heteroatom nucleophiles to heterocumulenes. Fig. 8.12. Mechanism of the uncatalyzed addition (starting top left and proceeding clockwise) and the acid-catalyzed addition (starting top left and then proceeding counterclockwise) of heteroatom nucleophiles to heterocumulenes.
The former chapter Additions of Heteroatom Nucleophiles to Heterocumulenes, Additions of Heteroatom Nucleophiles to Carbonyl Compounds and Follow-up Reactions has been spht into two separate chapters into Chapter 8 Carbonic Acid Derivatives and Heterocumulenes and Their Interconversion , whose systematic organization should represent a particularly valuable learning aid, and into Chapter 9 Additions of Het-eroatom Nucleophiles to Carbonyl Compounds and Follow-up Reactions—Condensations of Heteroatom Nucleophiles with Carbonyl Compounds. ... [Pg.870]

Additions of Heteroatom Nucleophiles to Heterocumulenes, Additions of Heteroatom Nucleophiles to Carbonyl Compounds and Follow-up Reactions... [Pg.271]

See other pages where Heterocumulenes heteroatom nucleophilic addition is mentioned: [Pg.340]    [Pg.342]    [Pg.348]    [Pg.357]    [Pg.271]    [Pg.271]    [Pg.271]    [Pg.272]    [Pg.272]    [Pg.273]    [Pg.274]    [Pg.275]    [Pg.276]    [Pg.277]    [Pg.278]    [Pg.280]    [Pg.282]    [Pg.284]    [Pg.286]    [Pg.288]    [Pg.290]    [Pg.292]    [Pg.294]    [Pg.296]    [Pg.298]    [Pg.300]    [Pg.302]    [Pg.304]   
See also in sourсe #XX -- [ Pg.256 , Pg.271 ]



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