Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Vinylketene acetals asymmetric Diels-Alder reaction

Lewis acid promoted reactions of silicon enolates, /.e., silyl enol ethers and ketene silyl acetals with various electrophiles have yielded a wealth of novel and selective synthetic methods. This combination of reagents has been used in the past to perform such reactions as aldol-condensations with aldehydes and acetals, imine-condensations, conjugate additions to a,P-enones, alkylations, electrophilic aminations, and Diels-Alder/cyclocondensations. Our own interest in this field has involved the use of titanium tetrachloride to promote the reaction of ketene silyl acetals with non-activated imines as an efficient route to P-lactams. This reaction has been applied to the asymmetric synthesis of P-lactams via a chiral imine-titanium tetrachloride template. We have also found that both ketene silyl acetals and vinylketene silyl acetals oxidativelly dimerize or cross-couple, in the presence of titanium tetrachloride to conveniently yield various diesters . Our present study concerns reactions of vinylketene silyl acetals with non-activated imines and vinylimines promoted by titanium and zirconium tetrachlorides. [Pg.37]


See also in sourсe #XX -- [ Pg.14 , Pg.503 , Pg.504 ]




SEARCH



Acetic Diels-Alder

Asymmetric Diels-Alder

Vinylketene

Vinylketene 0,0 acetals

Vinylketenes

Vinylketenes, Diels-Alder reaction

© 2024 chempedia.info