Categories: C-O Bond Formation > Synthesis of esters > Esterification, Transesterification, Acylation >
Asymmetric Acylations of Alcohols
Recent Literature
A highly efficient dynamic kinetic resolution (DKR) of
secondary alcohols at room temperature was developed. In situ racemization of
substrates using a Ru catalyst and lipase-catalyzed acylation provides
enantiopure products in high yields in very short reaction times. The use of
isopropenyl acetate as the acyl donor makes the purification of the products
very easy.
B. Martin-Matute, M. Edin, Krisztian Bogar, J.-E. Baeckvall, Angew. Chem.
Int. Ed.,
2004,
43, 6535-6539.
Benzylidene 1,1-diacetate is a sustainable and efficient acyl donor for
enzymatic acylation of chiral and nonchiral alcohols. Especially, unsaturated
acetates can be converted without E/Z isomerization. The acyl
donor can be recreated and reused. A dynamic kinetic resolution (DKR) protocol
results in chiral acetates in high yields and very high enantiomeric excesses.
D. Koszelewski, A. Brodzka, A. Madej, D. Trzepizur, R. Ostaszewski, J. Org. Chem., 2021, 86,
6331-6342.
The combination of lipase and a ruthenium complex catalyzes the asymmetric
transformation of enol acetates or ketones to chiral acetates in high yields
with high optical purities in the presence of 2,6-dimethylheptan-4-ol as a
hydrogen donor and 4-chlorophenyl acetate as an acyl donor.
H. M. Jung, J. H. Koh, M.-J. Kim, J. Park,
Org. Lett., 2000, 2, 397-399.
Ketones were transformed to chiral acetates by a one-pot process using a lipase
and an achiral ruthenium complex under 1 atm of hydrogen gas in ethyl acetate.
The same catalyst system was also effective for an asymmetric transformation of
enol acetates to acetates under hydrogen without additional acyl donors.
H. M. Jung, J. H. Koh, M.-J. Kim, J. Park,
Org. Lett., 2000, 2, 2487-2490.
Dynamic kinetic resolution (DKR) of various aromatic chlorohydrins using
Pseudomonas cepacia lipase (PS-C “Amano” II) and a ruthenium catalyst
afforded chlorohydrin acetates in high yields and high enantiomeric excesses.
These optically pure chlorohydrin acetates can be transformed to a wide range of
important chiral compounds.
A. Träff, K. Bogár, M. Warner, J.-E. Bäckvall, Org. Lett.,
2008,
10, 4807-4810.
A practical procedure has been developed for the dynamic kinetic resolution of
1,2-diarylethanols using a highly enantioselective lipase from Pseudomonas
stutzeri as the resolution catalyst and a ruthenium complex as the
racemization catalyst. Various 1,2-diarylethanols have been efficiently resolved
to provide their acetyl derivatives with good yields and high enantiomeric
excesses.
M.-J. Kim, Y. K. Choi, S. Kim, D. Kim, K. Han, S.-B. Ko, J. Park, Org. Lett., 2008,
10, 1295-1298.
Lipase-catalyzed acylation of racemic alcohols with a highly fluorinated acyl
donor allows their kinetic resolution and a subsequent, efficient partition of
both the tagged and untagged enantiomer
between a fluorous and an organic phase. The method has been successfully
applied to the resolution of secondary alcohols of low
molecular weight. The fluorous label can be recovered quantitatively.
B. Hungerhoff, H. Sonnenschein, F. Theil, J. Org. Chem, 2002,
67, 1781-1785.
A combination of a lipase and a ruthenium complex reaction enables a dynamic
kinetic resolution of allylic alcohols in which racemic substrates react in the
presence of an acyl donor to allylic acetates of high optical purity in very
good yields.
D. Lee, E. A. Huh, M.-J. Kim, H. M. Jung, J. H. Koh, J. Park,
Org. Lett., 2000, 2, 2377-2379.
The combination of a vanadium-oxo compound with a lipase enables the regio- and
enantioconvergent transformation of racemic allyl alcohols into optically active
allyl esters. In this dynamic kinetic resolution, the vanadium compounds
catalyzes both the racemization and the transposition of the hydroxyl group,
while the lipase effects the chemo- and enantioselective esterification.
S. Akai, R. Hanada, N. Fujiwara, Y. Kita, M. Egi, Org. Lett., 2010,
12, 4900-4903.