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Peterson olefmation

In 1968 Peterson published his results about the reaction of a-silylated carbanions with carbonyl compounds to achieve /3-hydroxyalkyl-silanes. He found that instantaneous elimination affords unsaturated hydrocarbons ( Peterson olefmation )180 Thus, the lithiated trimethyl-benzyl-silane (274) plus benzophenone (135) give via lithium l,l,2,-triphenyl-2-TMS-ethanolate (275) 1,1,2-triphenyl-ethene (276)180 ... [Pg.58]

The reductive cleavage of just one C-S bond yields the mono(lithiomethyl)silanes. This transformation is well known and used in the Peterson olefmation for the preparation of (lithiomethyl)trimethylsilane (15) [5], We employed it as a method to exchange the thiophenyl-group in the (phenylthiomethyl)silanes 5-14 with lithium, thus creating the corresponding poly(lithiomethyl)silanes (see, e.g.. Scheme 3 for methylsilanes) [4]. [Pg.501]

When 90 was heated in toluene, the hydroxylamine added to the alkyne to afford nitrone 91 (after tautomerization of a presumed intermediate N-hydroxyenamine) which was trapped by styrene in an intermolecular 1,3-dipolar cycloaddition to provide 92. An oxidation state adjustment (with removal of the chiral auxiliary) gave 93. The TBDPS protecting group was removed and the resulting primary alcohol was oxidized with IBX (94) (related to the Dess-Martin periodinane) to give aldehyde 95. Application of the Yamamoto variation of the Peterson olefmation gave 96 with decent control over olefin geometry. [Pg.354]

Chiral tridendate ligands have been utilized to effect asymmetric Peterson reactions, resulting in olefins with axial chirality in high yields and enantioselectivities. This is reported as the first example of its kind, namely the enantioselective Peterson olefmation of a-silanyl ester enolates 33 with substituted cyclohexanones 32, facilitated by an external chiral ligand 34. [Pg.524]

In an analogous fashion, unsaturated selenoamides 74 have also been generated via the Peterson olefmation reaction. The reaction proceeded with excellent yields. [Pg.530]

Roush and co-workers have effectively applied the Peterson olefmation conditions to synthesise cyclitol derivatives as intermediates in their approach towards the conduritol natural products. Starting from common precursors 97, both acidic and basic conditions were employed to give the desired alkenes 98/100 in excellent yields removal of the protecting groups then furnished the natural products 99/101. [Pg.533]

Floreancig and coworkers employed a sequential Peterson olefmation and Prins cyclisation reaction in their total synthesis of (+)-dactylolide hence neatly illustrating the versatility of the Peterson reaction. The P hydroxysilane 103 was synthesised in situ by the double addition of the necessary Grignard reagent onto ester 102. Treatment of the resulting tertiary alcohol with pyridinium triflate and magnesium sulfate then prompted the Peterson olefmation and subsequent Prins cyclisation to occur, affording tetrahydropyran 106 in 75% yield. [Pg.533]


See other pages where Peterson olefmation is mentioned: [Pg.43]    [Pg.168]    [Pg.231]    [Pg.546]    [Pg.431]    [Pg.431]    [Pg.563]    [Pg.567]   
See also in sourсe #XX -- [ Pg.176 , Pg.187 ]




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