Chiral methyl groups synthesis

Identify both pericyclic steps used in the synthesis 6.32 —> 6.33 of a chiral methyl group, and show that they obey the Woodward-Hoffmann rule. 

Caspi and co-workers (56) have reported the synthesis of n-octane containing a chiral methyl group by the displacement of the mesylate of (R)- and (S)-l-[l-3H]octanol with superdeuteride. A unique feature of their approach (56,57) was the chemical conversion of the more readily available tritiated IS alcohol, obtained from the reduction of [l-3H]octanal by horse liver alcohol dehydrogenase, to the more difficult-to-obtain 1/ alcohol by the Mitsunobu reaction. Using the conditions shown in Scheme 10, the (IS)-alcohol was converted to the (l/ )-benzoate which gave the (17 )-alcohol by reductive cleavage with LiAlH4. 

Synthesis of methionine and AdoMet carrying a chiral methyl group of known configuration. 

New Developments in the Synthesis of Polyketides and of Chiral Methyl Groups... 

This review deals with recent advances in the synthesis of polypropionate structures. It focuses on the total synthesis of natural products (citreoviral, ACRL toxin IECB) as well as on new synthetic methodology (chiral methyl branching, base induced 1,3-H-shift and chiral methyl groups). 

Since these early studies, numerous additional procedures have been developed for the synthesis of chiral labeled acetic acid and other chiral labeled molecules by chemical (I41-15I) and enzymic methods 152-155). The malate synthase/fumarase system described above continues to be the most widely used method for the stereochemical analysis of chiral labeled acetic acid resulting from the degradation of product molecules containing chiral methyl groups. 

Reactions.—1,3-Dithianyl Anions. 1,3-Dithianyl anions continue to find wide-ranging utility in the synthesis of diverse structures, including 2-deoxy-L-lyxose derivatives, eburnamine precursors, " l,2-diformyl-6,6-dimethylcyclohex-2-en-l-ol, cannabinoids, tertiary acyloins, cyclitols, unsaturated carboxylic acids, the terpenes egomaketone and a- and jff-curcumene, (205)-20-hydroxycholesterol, norpyrenophorin, pyrenophorin, and vermiculine, compounds with chiral methyl groups, " (+)-rrans-burseran, enones, " the macrocyclic lactam A-methylmaysenine, olivin, macrocyclic acetylacetone crown ethers, [5.1]metacyclophane, ( )-laurencin, monosaccharides, y-keto-esters and their precursors, muscarine analogues, quinols, epi-... 

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