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Mitsunobu-type reaction

Intermediate 331 was used in the reaction with ketone-derived sugars 133 (from D-glucose) or 270 (from D-fructose) and with the protected estrone 280 so that, after hydrolysis, diols 337-339"° " were obtained in 25-80% yield. Further cyclization of these diols under Mitsunobu-type reaction conditions (PPh3, DIAD, benzene reflux) gave the mixed heterocyclic sugars 340 and 341"°, and the steroid derivative 342", respectively, in 45-50% yield. [Pg.703]

In view of their applications in asymmetric synthetic methodology, chiral thiols are currently the subject of much attention. They can be derived from the natural chirality pool as epi-thiomenthol obtained by a Mitsunobu-type reaction [9]. A similar route to (S)-l-phenylethanethiol (2) has been described [10]. [Pg.8]

Reliable clean S 2 reactions with secondary allylic alcohols can be achieved only with Mitsunobu chemistry. Here is a well-behaved example with a Z-alkene. The reagents have changed since your last encounter with a Mitsunobu-type reaction instead of DEAD and a carboxylic acid we have hexa-chloroacetone. [Pg.608]

Fmoc-D-cycloserine (4-aminoisoxazolidine-3-one) and its enantiomer were immobilized on SASRIN resin or 2-chlorotrityl linker resins using Mitsunobu-type reaction or direct tritylation, respectively. The loading of the resulting resins (0.59-0.69 mmol g) was determined by spectrophotometry of the in rr/ -generated piperidine-dibenzofulvene... [Pg.421]

Inversion of the configuration of an alcohol by cesium carboxylate has also been demonstrated. This Mitsunobu-type reaction is sometimes more convenient than the classical phosphine-based reaction. Although a small amount of the E2 elimination reaction also occurs, carboxylation of the mesylate of the alcohol proceeds perfectly with inversion of configuration (Scheme 2.28) [44]. [Pg.45]

Miscellaneous Reactions. - p-Toluenesulfonaraide undergoes Mitsunobu-type reactions in the presence of alcohols and cyanomethylenetriphenyl-phos-phorane (56) to give predominantly mono-N-alkylation products. This reaction has also been applied to the synthesis of cyclic ethers from diols and cyclic amines from amino alcohols and to carbon-carbon bond formation. Examples of cyclic amine synthesis include that of (+)-a-skytanthine (57). A comparative study of the reactions of active methine compounds (58) as nucleophiles using... [Pg.246]

Mitsunobu type reactions with, 161 Phosphorous tribromide OH/Br exchange, 303 Phosphorous trichloride glycosyl halides, 266 Phosphorus(5 +) chloride ... [Pg.217]

Mitsunobu-type Reactions. The combination of triph-enylphosphine and DDQ can be used to activate alcohols and related substrates to nucleophilic displacement in a reaction which is related to the widely used Mitsunobu reaction (using triphenylphosphine and an azodicarboxylate) (eq 44). For... [Pg.159]

Addition of an enolate to a chiral aldehyde has also been used. In this interesting approach, addition of the enolate of 7,4.26 (formed in the presence of TiCU and Et3N) to the chiral benzaldehyde 7.4.25 gave the adduct 7.4.27. The chromium was removed from 7.4.27 by treatment with tetrabutylammonium fluoride followed by photolysis, and the azide group was introduced by a Mitsunobu-type reaction to give azide 7.4.28. This compound was then converted to the taxol side chain methyl ester by standard chemistry (276, 277). [Pg.121]

A convenient preparation has been reported of -adenosylhomocyste-ine (SAH, 33) from adenosine and a homocysteine derivative by a Mitsunobu-type reaction (Scheme 9). The 3- and 7-deazaanalogues... [Pg.201]

HCV protease inhibitor intermediate) 86 (azamacrocycles) Figure 11.11 Macrocycles produced using Mitsunobu-type reactions. [Pg.435]

Another approach toward the synthesis of aryliminophosphoranes (27) involved a Mitsunobu-type reaction between aromatic amines, diethyl azodicarboxylate (DEAD) and triphenylphosphine at ambient temperature. Pentacoordinated intermediate (28) was formed after nucleophilic addition of the conjugated base of the NH-acid on the Huisgen zwitterions (29). Thus fragmentation of the initial adduct (30) under the reaction conditions provided access to iminophosphoranes (27) after removal of the hydrazide (31) (Scheme 6). [Pg.200]


See other pages where Mitsunobu-type reaction is mentioned: [Pg.169]    [Pg.169]    [Pg.243]    [Pg.297]    [Pg.106]    [Pg.153]    [Pg.217]    [Pg.314]    [Pg.2]    [Pg.188]   
See also in sourсe #XX -- [ Pg.160 ]

See also in sourсe #XX -- [ Pg.160 ]

See also in sourсe #XX -- [ Pg.160 ]




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Mitsunobu

Mitsunobu reaction

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