Lemieux oxidation

The structure of futoenone (14.1a) was deduced through the careful interpretation of NMR spectra 114) aided by partial decoupling and observation of Overhauser effects 145) of the compound and such derivatives as the Lemieux oxidation products 80 and 81,... 

The next stage of the synthesis called for conversion of the terminal olefin to an aldehyde. This was accomplished using a Johnson-Lemieux oxidation. The resulting ketoaldehyde was then converted to fr-ketal 15. Basic hydrolysis of the formamide provided 16 and hydrolysis of the acetals afforded a mixture of diastereometic enaminoketones 17. An acid-promoted intramolecular Mannich reaction gave 2. Presumably epimerization of the ketone allowed both diastereomers of 17 to follow the path to 2. Reduction of ketone 2 with sodium borohydride provided an alcohol, which underwent formal dehydration upon treatment with thionyl chloride and pyridine, to give porantherine (1) as a racemic mixture. 

The projected Pd-mediated double cyclization was accomplished to give 82 in a good yield through a presumed intermediate of type 88. Johnson-Lemieux oxidative cleavage of the double bond gave ketone 87 which had previously been converted to morphine by the Rice group (NIH). 

A new remarkable side chain alkylation pattern has been found in calysterol, the principal sterol component of the sponge Calyx nicaensis 75a). Structure (181), reminiscent of those of gorgosterol (175) and its relatives (176) and (177), has been proposed for this unique sterol on the basis of spectral data (m.s. and n.m.r.) of the acetate, m.p. 105—106°, [a]o-34.3°, and Lemieux oxidation of the corresponding stanol to a p-diketone (182). Interestingly, calysterol (181) completely decomposes on an alumina-silver nitrate column to give four compounds the major one has been characterized as (182 a). 

MALAPRAOE LEMIEUX JOHNSON Olefin (dfoO cleavage Oxidative cleavage of 1,2-glycols to two cart nyls (Malaprade) or direct oxidation o( olefins IO4 and OSO4 catalyst (Lenveux Johnson)... 

The power of the new spectrometer to reveal configurations of difficult cyclitols or sugars was first tested with mt/o-inositol (2), using deuterium oxide as solvent. At 60 or 100 MHz. the one equatorial and five axial protons appear to have different chemical shifts as shown by Lemieux in 1956 with a 40 MHz. instrument (14,15). However, since the five-proton axial signal could not be resolved, one could probably not have assigned the configuration 2 (which was already known from laborious chemical correlations extending over many years.)... 

This cyclization reaction has been used in the synthesis of a number of A -substituted 5-hy-droxy-2-pyrrolidinones by Lemieux Johnson oxidation of the corresponding amides of the ( )- or (i5)-4-octene-l,8-dioic acids according to the procedure described. 

The oxidative cleavage by the procedure of Lemieux (9) was not convenient on a large scale due to the dilute reaction conditions, (7.5 L of 2 1 water 2-methyl-2-propanol) and the need for nine equivalents of relatively expensive sodium metaperiodate... 

Shammaet al. (144-146) utilized Hofmann degradation of 8-benzyltetrahy-droprotoberberine for selective C-8—N bond cleavage (Section II,A,1). Benzylidene products 17 and 271, derived from berberine (15) and coptisine (65), were subjected to Lemieux-Johnson-Pappu oxidation to provide (+)-canadaline (272) and ( )-aobamine (273), respectively, the latter of which was... 

A great number of transformations has been performed on narceine imide (116) by Czech researchers. Oxidation with potassium permanganate in acetone or with nitric acid caused the cleavage of the alkaloid, giving rise to hemipinic imide (127). A similar result was noted by Rdnsch (129,130) during Lemieux-Johnson oxidation of ene lactam 152 (129,130) in this reaction the basic component (156) was isolated as well. The use of hydrogen peroxide in acetone converted 116 to (Z)-narceine imide N-oxide, which under the action of acetic anhydride underwent N-dealkylation (135). 

A somewhat similar configurational correlation between (leva)-glyceraldehyde and (dexfro)-lactic acid has been made by Wolfrom, Lemieux, Olin and Weisblat.36 Reductive desulfurization of tetra-acetyl-2-methyl-D-glucose diethyl thioacetal (XXVII) and hydrolysis of the product gave 2-methyl-l-desoxy-D-glucitol (XXVIII) oxidation... 

Data from Polasek Jervis (1994), for pure tyre ash. Major elemeni oxides add up to only 71 wt% no further details available. Data from Lemieux (1994), collected after co-firing natural gas and TDF crumbs. Major element oxides add up to 85 and 87 wt%, respectively. Ash represents fly ash from combustion of TDF crumbs, whose fuel characteristics are listed in Tables 4 and 5. Lemieux (1994) suspected that some elements (Al, Si, Zr) may have originated from the rotary kiln insulation. 

Miller, C. A., Lemieux, P. M. Touati, A. 1998. Evaluation of tire-derived fuel for use in nitrogen oxide reduction by rebuming. Journal of the Air and Waste Management Association, 48, 729-735. 

The Proton Magnetic Resonance Spectra and Tautomeric Equilibria of Aldoses in Deuterium Oxide, R. U. Lemieux and J. D. Stevens, Can. J. Chem., 44 (1966) 249-262. 

Step 1 (3-keto phosphonates often are used for olefmation of ketones (Horner-Wadsworth-Emmons modification of the Wittig reaction). Steps 2 + 3 The cuprate-mediated 1,4-addition and subsequent Lemieux-Johnson oxidation of a vinyl group are excellent procedures for the introduction of the p-formyl group. 

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