The methyl esters of 3R,7S-dimethyl- and 3R,5R,7S-trimethyl-8-hydroxyoctanoic acids have been prepared in good yields and with e.e. >98% by chemical elaboration of the known exo,exo-3,7-dimethylbicyclo[3.3.1]nonan-9-one, the key step involving the desymmetrisation of the intermediate meso-ketones cis-3,7-dimethyl- and cis,cis-3,5,7-trimethyl-cyclooctanone through the corresponding chiral enolates generated by the lithium amide of the (+)bis[(R)-(1-phenylethylamine)]. The very high enantioselectivity observed might be related to the conformational features of the eight-membered ring.

Gambacorta, A., Tofani, D., Elmi Farah, M., Tafi, A. (2002). Desymmetrisation of meso-methylcyclooctanones. Highly Enantioselective Synthesis of C8 syn-Isoprenoid and syn,syn-Deoxypropionate Subunits from a Bicyclo[3.3.1]nonane Precursor. TETRAHEDRON LETTERS, 43(12), 2195-2198 [10.1016/S0040-4039(02)00229-0].

Desymmetrisation of meso-methylcyclooctanones. Highly Enantioselective Synthesis of C8 syn-Isoprenoid and syn,syn-Deoxypropionate Subunits from a Bicyclo[3.3.1]nonane Precursor

Tafi, Andrea
2002-01-01

Abstract

The methyl esters of 3R,7S-dimethyl- and 3R,5R,7S-trimethyl-8-hydroxyoctanoic acids have been prepared in good yields and with e.e. >98% by chemical elaboration of the known exo,exo-3,7-dimethylbicyclo[3.3.1]nonan-9-one, the key step involving the desymmetrisation of the intermediate meso-ketones cis-3,7-dimethyl- and cis,cis-3,5,7-trimethyl-cyclooctanone through the corresponding chiral enolates generated by the lithium amide of the (+)bis[(R)-(1-phenylethylamine)]. The very high enantioselectivity observed might be related to the conformational features of the eight-membered ring.
2002
Gambacorta, A., Tofani, D., Elmi Farah, M., Tafi, A. (2002). Desymmetrisation of meso-methylcyclooctanones. Highly Enantioselective Synthesis of C8 syn-Isoprenoid and syn,syn-Deoxypropionate Subunits from a Bicyclo[3.3.1]nonane Precursor. TETRAHEDRON LETTERS, 43(12), 2195-2198 [10.1016/S0040-4039(02)00229-0].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/45001
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