24892-67-9Relevant articles and documents
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Graf,Boeddeker
, p. 364,367 (1956)
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Reactions of phenyldimethylsilyllithium with β-N,N- dimethylaminoenones: A convenient synthesis of β-dimethyl(phenyl) silylacrylic acid and its derivatives
Fleming, Ian,Marangon, Elena,Roni, Chiara,Russell, Matthew G.,Chamudis, Sandra Taliansky
, p. 325 - 332 (2007/10/03)
Phenyldimethylsilyllithium reacted with 5,5-dimethyl-3-(N,N,-dimethylamino) cyclohex-2-enone (7), 3-(E)-N,N-dimethylaminopropenal (11), and 4-N,N-dimethylaminobut-3-en-2-one (13) to give the corresponding β-silyl-α,β-unsaturated carbonyl compounds 8, 12, and 14, in which the dimethylamino group has been displaced by the phenyldimethylsilyl group. Phenyldimethylsilyllithium reacted with ethyl β-N,N- dimethylaminopropenoate (15) by conjugate addition, but, in contrast to the ketones 7 and 13 and the aldehyde 11, the intermediate enolate 16 was C-protonated in the aqueous work-up to give ethyl 3-N,N-dimethylamino-3- dimethyl(phenyl)silylpropanoate (17). When the enolate 16 was instead given a mysteriously brief treatment with methyl iodide before work-up, the product was ethyl 3-(E)-dimethy(phenyl)silylpropenoate (18). Phenyllithium and methyllithium also added conjugatively to ethyl β-N,N-dimethylaminoacrylate (15) but, in contrast to the silyl case, the intermediate enolate 22 reacted unexceptionally with methyl iodide to give the products 25 and 26 of stereoselective C-methylation. This synthesis of the ester 18 was used to synthesize the Oppolzer sultam derivative 30.
Synthesis of 4-alkoxy and 3-nitro substituted isoxazolidines by catalyzed 1,3-dipolar cycloaddition reactions of nitrones with vinyl ethers and nitro alkenes
Meske, Michael
, p. 426 - 433 (2007/10/03)
1,3-Dipolar cycloadditions of the C-phenyl-N-alkylnitrones 1,3 and the C,N-diphenylnitrone (2) with vinyl ethers 5,6 are strongly catalyzed by chiral oxazaborolidines derived from N-arylsulfonyl substituted L-α-amino acids valine and tert-butyl leucine an
