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Allenyl enolate oxidation

The Diels-Alder reaction outlined above is a typical example of the utilization of axially chiral allenes, accessible through 1,6-addition or other methods, to generate selectively new stereogenic centers. This transfer of chirality is also possible via in-termolecular Diels-Alder reactions of vinylallenes [57], aldol reactions of allenyl eno-lates [19f] and Ireland-Claisen rearrangements of silyl allenylketene acetals [58]. Furthermore, it has been utilized recently in the diastereoselective oxidation of titanium allenyl enolates (formed by deprotonation of /3-allenecarboxylates of type 65 and transmetalation with titanocene dichloride) with dimethyl dioxirane (DMDO) [25, 59] and in subsequent acid- or gold-catalyzed cycloisomerization reactions of a-hydroxyallenes into 2,5-dihydrofurans (cf. Chapter 15) [25, 59, 60],... [Pg.67]

Zirconocene-derived allenyl enolate (6) was used for the synthesis of allenyl alcohol (7) (Equation 3) [4], Compared with the corresponding titanocene or lithium enolates derived from allenyl esters (5), zirconium enolates (6) gave alcohol (7) in better yields after oxidation with dimethyldioxolane. [Pg.297]


See other pages where Allenyl enolate oxidation is mentioned: [Pg.157]    [Pg.157]    [Pg.513]    [Pg.487]    [Pg.157]    [Pg.373]    [Pg.443]    [Pg.108]    [Pg.19]    [Pg.172]    [Pg.111]   
See also in sourсe #XX -- [ Pg.156 ]

See also in sourсe #XX -- [ Pg.156 ]




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Allenyl enolates, oxidation

Allenylation

Enolate, oxidation

Enolates oxidation

Enols oxidation

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