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Potassium diisopropylamide

The metallation of 1,3-diselenanes is complex. When potassium diisopropylamide is used as base, deprotonation and alkylation affords the 2-equatorially substituted derivative <96TL2667>. However, with rertbutyllithium, Se-Li exchange is observed in preference to H-Li exchange in the reaction with 2-ox-methylseleno derivatives <96TL8015>. The reaction with nBuLi either forms the anion or cleaves a C-Se bond depending on the substituents present at the 2-, 4- and 6- positions <96TL8011>. [Pg.309]

Asymmetric synthesis of 3-phcnylalkanaIs was realized by deprotonation of 2-methoxy-2-phenyl-l-[(T )-3-phenyl-2-propenyloxy]propane with potassium diisopropylamide (K.DA), followed by alkylation. The starting material is derived from ( )-3-bromo-l-phenyl-l-propene and (R)-2-methoxy-2-phenyl-l-propanol2. Alkylation occurred exclusively at the 3-position of... [Pg.680]

The dependence of the optical induction on the type of base and on the alkylating agent was investigated. The best results were obtained with potassium diisopropylamide in diethyl ether as base and iodoalkanes as alkylating reagents. [Pg.681]

Potassium diisopropylamide, 255 Desilylation (see also Hydrolysis of protected alcohols)... [Pg.363]

Butylsodium-Tetramethylethylene-diamine, 59 Lithium hydride, 165 Potassium /-butoxide, 252 Potassium diisopropylamide, 255 Potassium hexamethyldisilazide, 257 Potassium hydride, 257 Methoxylation... [Pg.368]

Luche to improve the yield. When the intermediate epoxy hydrazone is isolable, addition of a strong base, potassium r-butoxide or potassium diisopropylamide (KDA), improves the yield. Triethylamine is the base of choice in the case of an unstable epoxy hydrazone (equation I). [Pg.175]

Potassium-Graphite, 122, 378, 476 Potassium 3-aminopropylamide, 378-379 Potassium f-amyloxide, 378 379 Potassium benzeneselenolate, 373 Potassium bis(trimethylsilyl)amide, 229 Potassium f-butoxide, 7, 380-381 Potassium f-butoxide-Benzophenone, 382 Potassium carbonate, 382-383 Potassium dichromate, 383 Potassium diisopropylamide-Lithium t-butoxide, 383-384... [Pg.300]

Potassium diisopropylamide-Llthium r-butoxide (1). This nonnucleophilic strong base combination is stable in hexane at 0° for at least 1 hour. Potassium diisopropyl-amide alone is much less stable. The mixture (1) can be prepared in two ways addition of diisopropylamine to n-BuK-LiOC(CH3)3 in hexane at 0° or addition of n-BuLi to a solution of KOC(CH3)3 and diisopropylamine in THF at -78°. [Pg.498]

Potassium dichromate, 3 24 Potassium diisopropylamide, 324 Potassium ethanethiolate, 325 Potassium fluoride, 279, 325-326 Potassium formate, 329 Potassium-Graphite, 326 Potassium hexamethyldisilazide, 326-327 Potassium hydride, 327-328 Potassium hydrogen persulfate, 328 Potassium hydroxide-Alumina, 328 Potassium iodide-Boron(ill) iodide, 329 Potassium iodide-Zinc-Phosphorus(V) oxide, 329... [Pg.265]

Potassium diisopropylamide (KDA) has been advocated as an alternative to alkyllithium reagents and LDA as a means to form anions from N,N-dimethylhydrazones. The KDA for this purpose is prepared most conveniently in situ from Bu"Li, Bu OK and diisopropylamine. The principal advantage of KDA over lithium reagents is reportedly that its use produces anions from any hydrazone and generates them more rapidly. [Pg.506]

Potassium diisopropylamide, 255 Oi 5nLYtjinoN (ire o6o Hydrolysis of pto-leaed akohols)... [Pg.367]

Detailed investigations of conditions for metallations of 1,3-diselenanes by Krief and co-workers have led to useful procedures for these transformations <1996TL2667, 1996TL8011, 1996TL8015>. 1,3-Diselenanes are metallated by lithium diisopropylamide (LDA) or potassium diisopropylamide (KDA) in tetrahydrofuran (THF) at low temperature. The latter reagent appears to be more efficient, particularly in conformationally rigid systems (see Table 1, entries iii and iv). [Pg.799]

Related Reagents. Lithium Amide Lithium Hexamethyl-disilazide Lithium Diethylamide Lithium Piperidide Lithium Pyrrolidide Lithium 2,2,6,6-tetramethylpiperidide Potassium Diisopropylamide. [Pg.237]


See other pages where Potassium diisopropylamide is mentioned: [Pg.997]    [Pg.324]    [Pg.255]    [Pg.357]    [Pg.362]    [Pg.402]    [Pg.472]    [Pg.134]    [Pg.498]    [Pg.115]    [Pg.114]    [Pg.255]    [Pg.166]    [Pg.9]    [Pg.394]    [Pg.19]    [Pg.45]    [Pg.55]    [Pg.128]    [Pg.224]    [Pg.462]    [Pg.114]   
See also in sourсe #XX -- [ Pg.324 ]

See also in sourсe #XX -- [ Pg.255 ]

See also in sourсe #XX -- [ Pg.175 ]

See also in sourсe #XX -- [ Pg.255 ]

See also in sourсe #XX -- [ Pg.258 ]




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Bases Lithium diisopropylamide-Potassium

Bases Potassium diisopropylamide

Diisopropylamide

Lithium diisopropylamide-potassium

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