TY - JOUR
T1 - Enhanced diastereoselectivity via confinement
T2 - Diastereoselective photoisomerization of 2,3-diphenyl-1-benzoylcyclopropane derivatives within zeolites
AU - Sivaguru, J.
AU - Sunoj, Raghavan B.
AU - Wada, Takehiko
AU - Origane, Yumi
AU - Inoue, Yoshihisa
AU - Ramamurthy, V.
PY - 2004/8/20
Y1 - 2004/8/20
N2 - Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C1-C2 or C1-C3 bond. From the perspective of chiral induction, photoisomerization of cis-2,3-diphenyl-1-benzoylcyclopropane derivatives with chiral auxiliaries placed at the meta and para positions of the benzoyl group have been examined both in isotropic solution and within zeolites. Whereas in isotropic solution the chiral auxiliaries placed at the meta position exhibit very little influence during the conversion of triplet cis-2,3-diphenyl-1- benzoylcyclopropane derivatives, they have significant influence within zeolites. For example, α-methyl benzylamine placed at the meta position of the benzoyl group (via an amide bond) yields the trans isomer with a diastereoselectivity (de) of 71% within NaY zeolite, whereas in solution no de is obtained. The chiral induction process within zeolites depends on the nature of the alkali ion and on the presence of water. Results suggest that the chiral auxiliary is able to control the bond being cleaved (C1-C2 vs. C1-C3 bond) within a zeolite, but it is unable to do so in an isotropic solution.
AB - Photochemistry of optically pure trans-2,3-diphenyl-1-benzoylcyclopropane has been examined in isotropic solution and within zeolites. Results suggest that it isomerizes by cleavage of either the C1-C2 or C1-C3 bond. From the perspective of chiral induction, photoisomerization of cis-2,3-diphenyl-1-benzoylcyclopropane derivatives with chiral auxiliaries placed at the meta and para positions of the benzoyl group have been examined both in isotropic solution and within zeolites. Whereas in isotropic solution the chiral auxiliaries placed at the meta position exhibit very little influence during the conversion of triplet cis-2,3-diphenyl-1- benzoylcyclopropane derivatives, they have significant influence within zeolites. For example, α-methyl benzylamine placed at the meta position of the benzoyl group (via an amide bond) yields the trans isomer with a diastereoselectivity (de) of 71% within NaY zeolite, whereas in solution no de is obtained. The chiral induction process within zeolites depends on the nature of the alkali ion and on the presence of water. Results suggest that the chiral auxiliary is able to control the bond being cleaved (C1-C2 vs. C1-C3 bond) within a zeolite, but it is unable to do so in an isotropic solution.
UR - http://www.scopus.com/inward/record.url?scp=4043054973&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4043054973&partnerID=8YFLogxK
U2 - 10.1021/jo049697n
DO - 10.1021/jo049697n
M3 - Article
C2 - 15307720
AN - SCOPUS:4043054973
VL - 69
SP - 5528
EP - 5536
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
SN - 0022-3263
IS - 17
ER -