Enzymatic esterification of lavandulol – a partial kinetic resolution of (S)-lavandulol and preparation of optically enriched (R)-lavandulyl acetate

Abstract

The asymmetric esterification of the racemic primary alcohol lavandulol was achieved using lipase B from Candida antarctica and acetic acid as acyl donor in 80% yield. The enantioselectivity of the process was characterised, and a preparative resolution of 25 mM racemic lavandulol, stopped at approx. 55% conversion, yielded (S)-lavandulol in 42% yield and 52% e.e. and (R)-lavandulyl acetate in 51% yield and 48% e.e.

Identification of the Sex Pheromone of the Mealybug Dysmicoccus grassii Leonardi

“…Flash column chromatography with a product-to-phase load of 1:60 w/w using a 9:1 mixture of hexane/ethyl acetate as eluent afforded the corresponding acetate or propionate esters in 88 and 90% yield, respectively. Spectroscopic properties of synthesized lavandulyl acetates ( 1 H NMR, 13 C NMR, MS, and specific rotation) as well as specific rotation values for starting lavandulol isomers were in agreement with previously reported data . Purity and enantiomeric excess of the esters were estimated by means of chiral GC-FID direct integration of the starting chiral alcohols (ee = 98.7% for ( R )-lavandulol and ee = 99.5% for ( S )-lavandulol).…”

“…Spectroscopic properties of synthesized lavandulyl acetates ( 1 H NMR, 13 C NMR, MS, and specific rotation) as well as specific rotation values for starting lavandulol isomers were in agreement with previously reported data. 15 Purity and enantiomeric excess of the esters were estimated by means of chiral GC-FID direct integration of the starting chiral alcohols (ee = 98.7% for (R)lavandulol and ee = 99.5% for (S)-lavandulol).…”

Fungal mediated kinetic resolution of racemic acetates to ( R )-alcohols using Fusarium proliferatum

“…The fungal system was able to carry out the kinetic resolution of four racemic acyclic esters [(±)-lavandulyl acetate (1), (±)-2-hexyl acetate (2), (±)-2-heptyl acetate (3) and (±)-1-octen-3-yl acetate (5)] and three aromatic esters [(±)-1-phenylethyl acetate (6), (±)-3-methyl-1-phenylethyl acetate (8) and (±)-1-phenylpropyl acetate (9)] into corresponding (R)-alcohols in an efficient manner with high ee. Enantioselective hydrolysis of (±)-1-phenylethyl acetate (6) to (R)-(+)-1-phenylethanol (6a) was successfully scaled up to preparative scale, which indicated great potential of the developed process to be applied in large scale preparation of enantiopure (R)-alcohols.…”

“…Enzyme mediated kinetic resolution of such alcohols using lipases, esterases, and alcohol dehydrogenases have been reported in the literature. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] For example, resolution of (±)-lavandulol has been achieved previously with various lipases such as Candida antarctica lipase B (CAL B), 9 Hog pancreas lipase, 29 Porcine pancreas lipase, 26 and Yarrowia lipolytica lipases. 30 However, enzyme catalyzed resolution process is associated with several disadvantages such as higher cost, low substrate concentration, instability and cofactor dependency of the enzymes in several occasions.…”

Stereoselective Synthesis of Terpenoids through Lipase-Mediated Resolution Approaches

“…In spite of this fact, the natural enantiomer proved to possess better odor quality [16], if compared with the racemic material or with the (S)-enantiomer. A first resolution method was developed, using immobilized Candida antartica lipase (Novozym 435) as the catalyst and acetic acid as the acyl donor [17]. Even if the formed (R)-acetyl lavandulol was obtained in modest enantiomeric purity, the process holds industrial relevance, as it makes use of immobilized lipase and can be performed in supercritical carbon dioxide [18].…”