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Diastereoselectivity in scalemic tartrate/titanium epoxidations
Author(s) -
Brown John M.,
Leppard Simon J.,
Oakes John,
Thornthwaite David
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)12:5/6<496::aid-chir35>3.0.co;2-y
Subject(s) - chemistry , tartrate , reagent , allylic rearrangement , enantiomer , reactivity (psychology) , enantiomeric excess , titanium , organic chemistry , medicinal chemistry , enantioselective synthesis , catalysis , medicine , alternative medicine , pathology
Nonlinearity in the diastereoselectivity of epoxidation of allylic alcohols with mixtures of titanium isopropoxide, tert butyl hydroperoxide, and diethyl tartrate was observed. Racemic and enantiomerically pure alcohols E‐2‐methyl‐4‐hexen‐3‐ol and E‐1‐methoxy‐5‐(O‐ tert butyldimethylsilyloxy)‐2‐penten‐4‐ol were prepared. Epoxidation reactions were carried out with Ti(OPr i ) 4 and Bu t OOH accompanied by diethyl tartrate of varying enantiomeric purity. The simplest explanation of these results is that a dimeric epoxidation reagent is involved, with significantly different reactivity for the homochiral and racemic forms. Chirality 12:496–504, 2000. © 2000 Wiley‐Liss, Inc.