| 1. |
|
|
| 2. |
- Högberg, Hans-Erik, et al.
(author)
-
Biocatalysis as a useful tool in pheromone synthesis. Enantiomerically pure building blocks from baker's yeast reductions and enzyme catalysed resoluti
- 1994
-
In: Catalysis Today. - : Elsevier BV. - 0920-5861. ; 22:3, s. 591-606
-
Journal article (peer-reviewed)abstract
- Biocatalytical methods are presented which provide useful building blocks for pheromone synthesis. Examples of the utility of this approach are the preparation of building blocks for the synthesis of stereochemically pure isomers of pine sawfly pheromones and some other pheromones. Enantiom- erically pure ( 98% ee) 2-methyl-1-alkanols 2 were obtained via baker's yeast reduction of suitable α,β-unsaturated aldehydes, and by using lipases from Pseudomonas to effect resolution by transesterification of suitable racemic precursors to 2-methyl-1-alkanols 2 which gave high enantiomeric ratios E > 100. The resolution by esterification mediated by lipase from Candida rugosa of racemic 2-methylalkanoic acids also gave high enantiomeric ratios E> 100 after having improved the reaction conditions by regulating water activity, by choice of the appropriate complimentary substrate alcohol and by adjusting the initial equivalents of the latter present at the start. Also discussed is the separation of diastereomers of diprionol 1, which is naturally occurring in the pine sawfly Neodiprion sertifer, where it is the direct precursor of its pheromone.
|
|
| 3. |
|
|
| 4. |
- Nordin, Ove, et al.
(author)
-
Kinetic Resolution of Primary 2-methylalcohols via Pseudomonas cepacia Lipase Catalysed Enantioselective Acylation
- 2000
-
In: Journal of The Chemical Society. Perkin Transactions 1. - : Royal Society of Chemistry (RSC). - 1472-7781 .- 1470-4358 .- 1364-5463. ; , s. 367-376
-
Journal article (peer-reviewed)abstract
- The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E < 10), 2-methyl-4-(2-thienyl)butan-l-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-l-ol (E=3.2) and 2-methyl-6-(2-thienyl)hexan-l-ol (E=3.8).
|
|
| 5. |
|
|
