Regio- and stereoselective hydrogenation of methyl substituted pentadien-1-ols by baker's yeast

✍ Scribed by P. Gramatica; P. Manitto; D. Monti; G. Speranza

• Book ID: 104203575
• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 436 KB
• Volume: 44
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)85910-x

✦ Synopsis

In considering X=CHO Y=CH2OH X=Y= NO 2, CO2Et, CH2OH bukeh'b H tC0 Me w YWf-R/ 'CH2-Y ?J that a chiral building block must have different functionalities at the ends of a short aliphatic chain, in order to be widely applicable, we saw the possibility of obtaining chiral synthons of type 2 and 3 with R= -CH=CH2. The vinyl group is a very versatile function. In addition, having the double bond in a,fl-position to a CH2OH (or a COOH), such synthons represent a potential route to 6-and y-cyclic ethers or lactones7.

In this paper we wish to report that the enantiomerically pure chiral building blocks 2 and 2 can easily be obtained by baker's yeast reduction of the central double bond in the corresponding dienic alcohols 2 and 5 (Scheme).

5 was synthesized by Wittig condensation between acrolein and ethyl a-bromoprozionate followed by lithium aluminium hydride reduction of the resulting ester.

Only the desired (E)-configuration resulted from this Wittig reactionS. 2 was prepared by selective catalytic hydrogenation (Pd Lindlar and quinoline) of the commercial (E)-3-methyl-2-penten-4-in-l-01.

Baker's yeast reductions of 2 were performed at 32" C and pH=S for seven days.

In contrast, the microbiological reduction of Lwas slower: after ten days the reaction had gone to 80% completion. The reduction products were isolated in 2530%

yields by steam-distillation in diethyl ether and subsequent flash chromatography.

Care must be taken in the recovery of the fermentation products, because of the high volatility of these alcohols.

'Part 5 of the series *Microbial-mediated syntheses of EPC". For Part 4 see ref.

4e.