Nucleophiles three-carbon

Substitution of an additional nitrogen atom onto the three-carbon side chain also serves to suppress tranquilizing activity at the expense of antispasmodic activity. Reaction of phenothia zine with epichlorohydrin by means of sodium hydride gives the epoxide 121. It should be noted that, even if initial attack in this reaction is on the epoxide, the alkoxide ion that would result from this nucleophilic addition can readily displace the adjacent chlorine to give the observed product. Opening of the oxirane with dimethylamine proceeds at the terminal position to afford the amino alcohol, 122. The amino alcohol is then converted to the halide (123). A displacement reaction with dimethylamine gives aminopromazine (124). ... 

Finally, an ingenious synthetic sequence by Trost, Cossy and Burks201 includes a unique desulphonylation reaction that involves an electron-transfer process. The synthetic sequence uses 1, l-bis(phenylsulphonyl)cyclopropane as a source of three carbon atoms, since this species is readily alkylated even by weakly nucleophilic species. Given an appropriate structure for the nucleophile, Trost found that desulphonylation with lithium phenanthrenide in an aprotic solvent allowed for an efficient intramolecular trapping of the resultant carbanion (equation 88). This desulphonylation process occurs under very mild conditions and in high yields it will undoubtedly attract further interest. 

The asymmetric alkylation of a carbonyl group is one of the most commonly used chirality transfer reactions. The chirality of a substrate can be transferred to the newly formed asymmetric carbon atom through this process. In surveying chiral enolate systems as a class of nucleophile, three general subdivisions can be made in such asymmetric nucleophilic addition reactions intra-annular, extra-annular, and chelation enforced intra-annular. 

Three groups of polar processes to form aziridines are shown in Scheme 16. In every case, each of the two reactants must be capable of acting formally as either a bis-nucleophile or a bis-electrophile, or they must each have both nucleophilic and electrophilic character. In the aza-Darzens route (B-83MI 101-01, 84CHEC-(7)47), the imine acts as an electrophile at carbon and later as a nucleophile at nitrogen, while the a-haloenolate acts initially as a nucleophile at carbon and later as an electrophile at the same carbon. The roles of the two components are reversed for the polar aziridination route, which is related to the epoxidation reaction. In the last route, the 1,2-dihalide or a-haloenone acts formally as a bis-electrophile while the amine acts as a bis-nucleophile. 

Carlson, R. M. Oyler, A. R. Peterson, J. R. Synthesis of substituted 5,6-dihydro-2H-pyran-2-ones. Propiolic acid dianion as a reactive three-carbon nucleophile. J. Org. Chem. 1975, 40, 1610-1616. 

The selenetanes that have been described in the literature have been constructed via three types of reactions. Selenetane derivatives are generally prepared via the [2+2] two-component syntheses (Schemes 8 and 9 Equations 3-7). The [1+3] two-component syntheses via the reaction of a selenium nucleophile with a three-carbon unit have been carried out (Scheme 6, and Equations 8-10, 12, and 13). One-component syntheses via rearrangement-cyclization have also been performed (Scheme 7). 

These substitution products A and B need not be the final product of the reaction of nucleophiles with carboxyl species. Sometimes they may be formed only as intermediates and continue to react with the nucleophile. Being carbonyl compounds (substitution products A) or carboxylic acid derivatives (substitution products B), they can in principle undergo, another addition or substitution reaction (see above). Thus, carboxylic acid derivatives can react with as many as two equivalents of nucleophiles, and carbonic acid derivatives can react with as many as three. 

Appropriately substitued alkynyl iodonium salts afforded with nucleophiles cyclopentene derivatives. This annulation can be either [5 + 0], when all carbon atoms come from the alkyl chain of the alkynyl moiety, or a [2 + 3] process, in which three carbon atoms come from the nucleophile. Competition between [5 + 0] and [2 + 3] annulation may occur in some cases. 

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