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Synthesis of Enantiopure Aliphatic Acetylene Alcohols and Determination of Their Absolute Configurations by 1 H NMR Anisotropy and/or X‐ray Crystallography
Author(s) -
Sekiguchi Satoshi,
Akagi Megumi,
Naito Junpei,
Yamamoto Yoko,
Taji Hiromi,
Kuwahara Shunsuke,
Watanabe Masataka,
Ozawa Yoshiki,
Toriumi Koshiro,
Harada Nobuyuki
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200800012
Subject(s) - enantiopure drug , chemistry , diastereomer , acetylene , absolute configuration , solvolysis , yield (engineering) , organic chemistry , stereochemistry , catalysis , enantioselective synthesis , hydrolysis , materials science , metallurgy
Abstract The MαNP acid method has been applied to racemic aliphatic acetylene alcohols in order to simultaneously prepare enantiopure alcohols and to determine their absolute configurations by 1 H NMR anisotropy. Racemic acetylene alcohols 6 – 8 , 11 , and 20 were esterified with MαNP acid ( S )‐(+)‐ 1 to yield diastereomeric MαNP esters which were efficiently separated by HPLC on silica gel with separation factors α in the range 1.60–1.93. The 1 H NMR anisotropy factors Δ δ [= δ (2nd fr.) – δ (1st fr.)] were calculated from the data of the first‐ ( 22a – 27a ) and second‐eluted MαNP esters ( 22b – 27b ). The absolute configurations of the first‐eluted esters were determined from the distribution of Δ δ values in the MαNP sector rule. In the case of MαNP ester 26b , the assigned absolute configuration was confirmed by X‐ray crystallography. The solvolysis of MαNP esters yielded enantiopure acetylene alcohols 5 – 8 with established absolute configurations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)