Benzyl acetone → 4-Phenyl-2-butanol, (2S)-

Participants

Reaction Steps

Phenyl ring-containing 2-butanone derivatives were reduced to the corresponding (S)-alcohols with excellent stereoselectivities and moderate to excellent yields (Table 4). 4-Phenyl-2-butanone (1a) was reduced stereoselectively to produce (S)-4-phenyl-2-butanol ((S)-1b) with excellent chemical and optical yields. The â-diketone 1-phenyl-1,3-butadione (2a) was reduced regio- and stereoselectively to furnish the monohydroxy ketone (S)-3-hydroxy-1-phenyl-1-butanone ((S)-2b) with excellent yield and ee, leaving the other keto group at C-1 intact. (E)-4-Phenyl-3-butene-2-one (3a) was reduced with moderate yield and excellent optical purity to produce the allylic alcohol (S)-4-phenyl-3-butene-2-ol ((S)-3b). The presence of the methoxy group at the para position of the phenyl ring in 4-(4-methoxyphenyl)-2-butanone (4a) affected the ee of the produced (S)-4-(4-methoxyphenyl)-2-butanol ((S)-4-b) (91% ee), which was lower than for (S)-1b. Phenoxy-2-propanone (5a) was reduced with very high yield and optical purity to produce the corresponding (S)-phenoxy-2-propanol ((S)-5b). When the R-chloroketone, 3-chloro-4-(4-chlorophenyl)-2-butanone (6a), was reduced with W110A TESADH, (+)-(2S,3R)-3-chloro-4-(4-chlorophenyl)-2-butanol ((+)-(2S,3R)-6b) was produced with high enantioselectivity (>99% ee) and diastereoselectivity (92:8 mixture of anti- and syn-R-chlorohydrins).

Provenance & Evidence