Page 377 - Cascade_Biocatalysis_Integrating_Stereoselective_and_Environmentally_Friendly_Reactions

16.3 Carbohydrates and Other Polyhydroxylated Compounds 353

Table 16.1 Aldol additions of glycolaldehyde, hydroxyacetone, dihydroxyacetone, and
hydroxybutanone to different aldehydes.
O

R 2 OH O
O
OH 2 R : H CH CH OH CH CH
2
R 1 R 1 R a b 3 2 c d 2 3
FSA/TalB OH
O OH O OH O OH O OH O
HO R 2 R 2 R 2 R 2 R 2
OH OH OH OH OH
41 42 43 44 45
OH O OH O OH O OH O
Ph 2 Cl 2 Br 2 2
R R R S R
OH OH OH OH
46 47 48 49
OH O O OH O
BnO
R 2 O R 2
OH OH
50 51
O OH O OH H C O OH H C O OH O OH
3
BnO R 2 R 2 3 R 2 H C R 2 OPO 3 2− R 2
3
HO OH HO OH HO OH HO OH HO OH
52 53 54 55 56
OH HO
OH OH OH
O R 2 2
O R 2 O R 2 OH O R
OH HO OH HO OH
HO HO HO OH OH
57 58 59 60

Entry R 1 R 2 Product FSA w-t FSA A129S TalB F178Y

1 H H 41a >98 — —
2 H CH 41b 95 b — —
3
3 H CH OH 41c — 68 —
2
4 CH CH OH 42c — 71 —
3 2
5 CH CH 3 CH 3 43b >75 — >25<75
2
6 CH CH CH OH 43c >25<75 — >25<75
2 3 2
7 CH CH CH CH 43d >25<75 — nr
2 3 2 3
8 CH CH CH 3 CH 3 44b 90 b — —
2
2
9 CH CH(CH ) CH OH 45c — 77 —
2 3 2 2
10 CH Ph H 46a 40, 28 a — —
2
(continued overleaf )