Stereospecific intramolecular Michael addition to (−)-carvone based on temporary sulfur connection
1998; Elsevier BV; Volume: 39; Issue: 19 Linguagem: Inglês
10.1016/s0040-4039(98)00327-x
ISSN1873-3581
AutoresMario D. Bachi, Yaroslav V. Bilokin, Artem Melman,
Tópico(s)Molecular spectroscopy and chirality
ResumoAn acetic acid residue (CH2CO2Me) was stereoselectively attached to (−)-carvone (7) to give (1R,2S,5R)-(5-isopropenyl-2-methyl-3-oxocyclohexyl)acetic acid methyl ester (21) in a process involving the following stages: i) addition of ClSCH2CO2Me to the isopropenyl group of 7 to give, after oxidation, [1-chloro-2(RS)-(1(R),4-methyl-5-oxocyclohex-3-enyl)propane-2-sulfonyl]acetic acid methyl ester (18); ii) intramolecular Michael addition of 18 to afford (1S,2S,4(RS),5R,8S)-4-chloromethyl-4,8-dimethyl-3,3,7-trioxo-3-thiabicyclo [3.3.1]nonane-2-carboxylic acid methyl ester (20); iii) disconnection of the acetic acid moiety by a tandem reductive elimination involving sulfur extrusion and restoration of the isopropenyl group (20 → 21).
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