Biomimetic Organocatalytic C–C-Bond Formations
103
of substrates 128 (R
1 = 2,4-di-t-Bu) caused much lower conversions
with pre-catalyst 127 even after long reaction times. By running the reaction at 45°C the conversion could be improved (Scheme 35).
The absolute configuration of chromanone 129 (R
1 = 2,4-di-Br,
R
2 = i-Bu) was assigned by X-ray analysis of the corresponding (S)Fig. 14. X-ray analysis of (S)-camphanylester 130
103
of substrates 128 (R
1 = 2,4-di-t-Bu) caused much lower conversions
with pre-catalyst 127 even after long reaction times. By running the reaction at 45°C the conversion could be improved (Scheme 35).
The absolute configuration of chromanone 129 (R
1 = 2,4-di-Br,
R
2 = i-Bu) was assigned by X-ray analysis of the corresponding (S)Fig. 14. X-ray analysis of (S)-camphanylester 130