Page 238 - Advanced Organic Chemistry Part A - Structure and Mechanisms, 5th ed (2007) - Carey _ Sundberg

218 Scheme 2.13 shows a few examples of resolutions and desymmetrization using
esterases. Entry 1 shows the partial resolution of a chiral ester using a crude enzyme
CHAPTER 2
source. The enantioselectivity is only moderate. Entries 2 to 5 are examples of
Stereochemistry, desymmetrization, in which prochiral ester groups are selectively hydrolyzed. Entries
Conformation,
and Stereoselectivity 6 and 7 are examples of selective hydrolysis of unsaturated esters that lead to
isomeric monoesters. These cases are examples of diastereoselectivity. In Entry 8, the
R,R-enantiomer of a racemic diester is selectively hydrolyzed. In all these cases, the

Scheme 2.13. Representative Resolutions and Desymmetrizations Using Esterases

bovine liver
acetone powder CH (CH ) CH=CH + CH 3 (CH ) CH=CH
1 a CH 3 (CH ) CHCH=CH 2 3 2 4 2 2 4 2
2 4
O CCH 3 77% e.e. OH 36% e.e. O CCH 3
2
2
O CCH 3 O CCH 3
2
2
2 b PLE HO2C CO 2CH
CH O C CO CH 3
3
2
2
3
pH 7
48% yield, R- enantiomer, 75% e.e.
3 2
3 c (CH 3 ) 2 CHCH(CO 2 C 2 H 5 ) 2 PLE (CH ) CH CO 2 H
C H S -enatiomer, 92% e.e.
CO 2 2 5
CO CH 3 CO CH
2
4 d PLE 2 3
CO CH 3 pH 7 CO H 96% yield, 88% e.e.
2
2
5 e O
O O
O
PLE
HO CCH O
CH O CCH 2 O 2 2
2
3
CH CO CH 3 CH CO CH 3
2
2
2
2
R-enantiomer, 90% e.e.
6 f CH 3 CO CH 3 PLE CH 3 CO CH CH CO H
2
2
3
+ 3 2
C H CO CH 3 C H CO H C H CO 2 CH 3
2 5
2 5
2
2 5
2
80% 20%
7 g CH 3 H PLE CH 3 H + CH 3 H
HO C CO CH CH 3 O 2 C CO 2 H
CH O C CO CH 3 2 2 3
2
2
3
95% 5%
O CCH OH
8 h 2 3 PLE
two phase
O CCH 3 buffer/hexane OH
2
racemic R,R-enantiomer
94% e.e. at 34% conversion
a. D. Basavaiah and S. B. Raju, Tetrahedron, 50, 4137 (1994).
b. B. Loubinoux, J.-L. Sinnes, A. C. O’Sullivan, and T. Winkler, Tetrahedron, 51, 3549 (1995).
c. B. Klotz-Berendes, W. Kleemis, U. Jegelka, H. J. Schaefer, and S. Kotila, Tetrahedron: Asymmetry, 8, 1821 (1997).
d. I. Harvey and D. H. G. Crout, Tetrahedron: Asymmetry, 4, 807 (1993).
e. R. Chenevert, B. T. Ngatcha, Y. S. Rose, and D. Goupil, Tetrahedron: Asymmetry, 9, 4325 (1998).
f. T. Schirmeister and H. H. Otto, J. Org. Chem., 58, 4819 (1993).
g. R. Schmid, V. Partali, T. Anthonsen, H. W. Anthonsen, and L. Kvittingen, Tetrahedron Lett., 42, 8543 (2001).
h. G. Caron and R. J. Kazlauskas, J. Org. Chem., 56, 7251 (1991).