Pchiral phosphoroacetates

Resolution of various racemic P-chiral phosphorylacetates 70 involved the same approach as was shown for sulfinylcarboxylates (Scheme 2). However, unlike the case of sulfinyl compounds, only PLE proved efficient for their P(O) analogues.

Scheme 6

Thus, a series of racemic phosphinylacetates,83'84 phosphonylacetates85'86 and phos-phorylacetates85'86 were resolved into enantiomers via their PLE-promoted hydrolysis to give products in high yields and with high ees (Equation 33). The most representative, selected examples are collected in Table 7.

The same methodology was applied to the desymmetrization of prochiral phenylphosphinyldiacetate 72. As a result, the monoester 73 was obtained in good yield but with moderate ee (Equation 34).87

Table 7

Enzymatic hydrolysis of phosphoryl-acetates 70

Recovered ester 70

Acid 71

Ref.

Table 7

Enzymatic hydrolysis of phosphoryl-acetates 70

Recovered ester 70

Acid 71

Ref.

(%)

[«]d

ee (%)

(%)

[a]D

ee (%)

Abs. conf.

1

Ph

Me

Me

50

+22

82

R

42

-22.2

82

S

n.r.

83,84

2

Ph

Et

Me

45

+09.7

>96

R

41

-8.2

81

S

n.r.

83,84

3

Ph

ch2=ch

Me

40

-54

-100

S

22

+54.5

n.d.

R

n.r.

83,84

4

Ph

MeO

Me

40

-16

95

S

44

+9.1

64

R

n.r.

85

5

PhO

MeO

Et

42

-10

99

n.d.

52

n.r.

77

n.d.

39

86

6

PhO

EtO

Me

66

-3.0

20

n.d.

22

+8.7

52

n.d.

n.r.

85

7

PhO

EtO

Et

46

n.r

86

n.d.

53

n.r.

73

n.d.

17

86

8

CF3CH2

MeO

Me

43

-6.2

99

S

53

+5.2

82

R

52

86

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