Entry

[H]

Solvent

Temp. [˚C]

Time [hours]

aYield of 21%

1

NaBH4

MeOH

0 ? r.t.

2

98

2

NaBH4

MeOH

−10

24

99

3

N(CH3)4BH4

MeOH

−10

24

94

4

N(CH3)4BH4

MeOH

0 ? r.t.

7

88