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Ylid s

The most convincing evidence concerning the relative stabilities of thiophene S,C-ylids, S,N-ylids, and the sulfoxides comes from ab initio restricted Hartree-Foch molecular orbital (MO) calculations, in which the molecular parameters of the ylid 18 and the S-methyl thiophenium salt 19 were compared (84CC859). The ylid (18) has never been isolated, nor would one intuitively expect it to enjoy any real stability. However, it was chosen to simplify the MO calculations. The stability of ylids such as 14 and 15 is almost certainly due to the ability of these systems to delocalize the formal negative charge over several atoms, and clearly this facility is not present in 18. Thus, 18 represents a highly localized ylidic structure. In principle, the salt 19 can be... [Pg.164]

N-Ylids s. 22,708 also cyclic N-oxides with hydroxylamines in place of hydrazines s. Y. Tamura and N. Tsujimoto, Chem. Ind. 1970, 926 Chem. Pharm. Bull. 19, 130, 143 (1971)... [Pg.135]

As-Ylids s. Arsonium ylids Bi-Ylids s. Bismuthonium ylids I-Ylids s. lodonium ylids N-Ylids, cyclic... [Pg.261]

As-Ylids (s. a. Arsonium ylids) reactions via - 16, 893 suppl. 26 N-Ylids, cyclic... [Pg.318]

P-Ylids s. Alkylidene-phosphoranes, Phosphonium ylids, cyclic, Ring-0,P-ylids... [Pg.318]

Sodium tetrahydrido borate I irradiation Hydrocarbons from sulfoxonium ylids s. 27,82... [Pg.335]

N, N-heterocyclics, N-condensed 22, 708 P-Ylids s. a. Alkylidene-phosphoranes stable... [Pg.295]

See other pages where Ylid s is mentioned: [Pg.251]    [Pg.251]    [Pg.283]    [Pg.522]    [Pg.218]    [Pg.97]    [Pg.270]    [Pg.283]    [Pg.291]    [Pg.300]    [Pg.300]    [Pg.261]    [Pg.261]    [Pg.261]    [Pg.300]    [Pg.312]    [Pg.318]    [Pg.450]    [Pg.361]    [Pg.36]    [Pg.284]    [Pg.144]    [Pg.271]    [Pg.295]   


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Ylid

Ylids

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