Publication

A new, non-iterative asymmetric synthesis of long-chain 1,3-polyols

Pierre Vogel
2000
Journal Articles

Abstract

A new approach to the asymmetric synthesis of pentadeca-1,3,5,7,9, 11,13,15-octols and their derivatives is presented. It is based on the Sharpless asymmetric dihydroxylation (AD) of 4,4'-methylene[(1R,1'S,6R,6'S)-6-acet-oxycyclohept-3-en-1-yl]bis(4-metho xy-benzoate) (9), derived from a double [3+4] cycloaddition of the 1,1,3-trichloro-2-oxyallyl cation with 2,2'-methylenedifuran (1). The diol (-)-10, obtained in 98.4% ee from 9 with "AD-mix-beta (5x ), was oxidised into (2R and 2S,6S,6R)-tetrahydro-2-hydroxy-6-{(4S,6S)-{6-hydroxy-4-[(4-methoxybenzoy l)oxy]cyclohept-1-en-1-yl}-2-oxopropyl)-2H-pyran-4-yl 4-methoxybenzoates ((-)-18). By the combinations of Evans' anti and Nasaraka's syn reductions of aldol (-)-18 with the double Mitsunobu reaction, 16 diastereomeric pentadeca-1,3,5,7,9,11,13,15-octols and analogues can be obtained, in principle, with high enantio- and diastereoselectivities.

Official source

https://infoscience.epfl.ch/entities/publication/0fb761a3-6862-4a8a-b5e3-d82065a1f0db

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Pierre Vogel
2000
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/0fb761a3-6862-4a8a-b5e3-d82065a1f0db

About this result

Related concepts (7)

Enantioselective synthesis

Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer.

Asymmetric induction

Asymmetric induction (also enantioinduction) describes the preferential formation in a chemical reaction of one enantiomer or diastereoisomer over the other as a result of the influence of a chiral feature present in the substrate, reagent, catalyst or environment. Asymmetric induction is a key element in asymmetric synthesis. Asymmetric induction was introduced by Hermann Emil Fischer based on his work on carbohydrates. Several types of induction exist.

Osmium tetroxide

Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4. The compound is noteworthy for its many uses, despite its toxicity and the rarity of osmium. It also has a number of unusual properties, one being that the solid is volatile. The compound is colourless, but most samples appear yellow. This is most likely due to the presence of the impurity OsO2, which is yellow-brown in colour. In biology, its property of binding to lipids has made it a widely-used stain in electron microscopy.