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Synthesis of the rac ‐6‐hydroxy‐3‐methoxycyclohex‐2‐enone and resolution through recrystallization of its diastereomeric N‐tosyl‐( S )‐proline esters
Author(s) -
Zaitsev V.G.,
Sachava D.G.,
Yankovskaya G.S.,
Garbuz N.I.
Publication year - 2000
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(2000)12:4<287::aid-chir15>3.0.co;2-n
Subject(s) - diastereomer , chemistry , enone , recrystallization (geology) , stereochemistry , circular dichroism , cyclohexene , cotton effect , absolute configuration , resolution (logic) , organic chemistry , paleontology , artificial intelligence , computer science , biology , catalysis
The synthesis and resolution of rac ‐6‐hydroxy‐3‐methoxycyclohex‐2‐enone, by fractional crystallization of diastereomeric esters of N‐protected ( S )‐proline was shown to be an effective method for preparation of both pure diastereomers (>95% d.e., according to 1 H NMR data). The absolute configuration of the asymmetric center in cyclohexene ring was determined based on the inversed octant rule for the sign of circular dichroism for these cyclohexenones (n‐π*‐transition band at ∼300 nm) and further substantiated by chemical conversion of the (−)‐(6 R, 2′ S )‐diastereomer into the known (+)‐( R )‐4‐hydroxycyclohex‐2‐enone. Chirality 12:287–290, 2000. © 2000 Wiley‐Liss, Inc.