Chiral discrimination of cryptochiral saturated quaternary and tertiary hydrocarbons by asymmetric autocatalysis.
Chiral discrimination of saturated hydrocarbons has been very difficult to establish, or has not been possible at all. The first chiral discrimination of cryptochiral 5-ethyl-5-propylundecane 1, that is, (n-butyl)ethyl(n-hexyl)(n-propyl)methane, a chiral saturated quaternary hydrocarbon, which is known to exhibit practically no detectable value of optical rotation between 280 and 580 nm, has been accomplished by asymmetric autocatalysis of pyrimidyl alkanol. The absolute configuration of 1 has been determined. In the presence of (R)- or (S)-1, the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc affords (S)- and (R)-pyrimidyl alkanol with 91-97% ee, respectively. Thus, asymmetric autocatalysis serves as a powerful tool for the chiral discrimination of saturated hydrocarbons.
Kawasaki
Tsuneomi
T
Department of Applied Chemistry, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo, 162-8601 Japan.
Tanaka
Hiroyuki
H
Tsutsumi
Takashi
T
Kasahara
Toshinari
T
Sato
Itaru
I
Soai
Kenso
K