TY - JOUR
T1 - Eliminations from 1-phenyl-2-alkyl tosylates promoted by MeONa in MeOH. Steric effects in alkene-forming elimination
AU - Cho, Bong Rae
AU - Han, Man So
PY - 1993
Y1 - 1993
N2 - Reactions of PhCH2CH(OTs)R [R = Me (1), Et (2), Pri (3), Bus (4), But (5)] with MeONa in MeOH have been studied. The reactions produce both conjugated and unconjugated alkenes. The yields of the conjugated alkenes are nearly the same for 1-4, while the E/Z ratios depend strongly upon the α-alkyl group. The rates of eliminations forming the conjugated E alkenes are decreased by a bulkier alkyl group as indicated by the relative rate of 1, 0.8, 0.7, 0.6, 0.2 for 1, 2, 3, 4, 5, respectively. On the other hand, the relative rates for the formation of the unconjugated alkenes are 1,1.7, 2.8,1.9 for 1, 2, 3, 4, respectively, indicating that the rate increases with the double bond stabilizing ability of the alkyl groups and decreases with their steric effect. From these results, the relative steric effect of the α- and β-alkyl groups in alkene-forming elimination is assessed.
AB - Reactions of PhCH2CH(OTs)R [R = Me (1), Et (2), Pri (3), Bus (4), But (5)] with MeONa in MeOH have been studied. The reactions produce both conjugated and unconjugated alkenes. The yields of the conjugated alkenes are nearly the same for 1-4, while the E/Z ratios depend strongly upon the α-alkyl group. The rates of eliminations forming the conjugated E alkenes are decreased by a bulkier alkyl group as indicated by the relative rate of 1, 0.8, 0.7, 0.6, 0.2 for 1, 2, 3, 4, 5, respectively. On the other hand, the relative rates for the formation of the unconjugated alkenes are 1,1.7, 2.8,1.9 for 1, 2, 3, 4, respectively, indicating that the rate increases with the double bond stabilizing ability of the alkyl groups and decreases with their steric effect. From these results, the relative steric effect of the α- and β-alkyl groups in alkene-forming elimination is assessed.
UR - http://www.scopus.com/inward/record.url?scp=37049083948&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=37049083948&partnerID=8YFLogxK
U2 - 10.1039/p29930000105
DO - 10.1039/p29930000105
M3 - Article
AN - SCOPUS:37049083948
SN - 0300-9580
SP - 105
EP - 108
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 1
ER -