Non-carbohydrate-based enantioselective synthesis of D(−)-allomuscarine

✍ Scribed by Giovanni Fronza; Claudio Fuganti; Piero Grasselli

• Publisher: Elsevier Science
• Year: 1978
• Tongue: French
• Weight: 140 KB
• Volume: 19
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)95104-4

✦ Synopsis

Among the easily accessible chiral products used as starting materials for enantioselective 1 syntheses of natural products, carbohydrates have received the widest attention. In the series of muscarine and its isomers, the C6 chiral framwork of L(+)-muscarine (12) has been built up2 from L-arabinose through the intermediacy of L-glucoeaminic acid, which ring closes to L-chitaric acid upon deamination, whereas D(-)-epiallomuscarine has been recently obtained3 from D-glucose.

However, in the abovementioned procedures, difficulties arise in the regioselective removal of oxygen functions, which cause low yield or the necessity of separation of isomers.

We report now the enantioselective non-carbohydrate-based formal synthesis of D(-)allo-4 muscarine (ll), which occurs in Amanita muscaria, using as chiral starting material the optically active, C6-C5 methyl diol (l), prepared from cinnamaldehyde and fermenting baker's yeast? Indeed, the diol (1) shows the (22,3lJ absolute configuration present in positions 5 and 4 of L(+)-muscarine (12) and D(-)-allomuscarine (ll), and seemed suitable for conversion through