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  • 02월 22일 16시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

Origin of the α-Effect : Reactions of Y-substituted-Phenyl Phenyl Carbonates with Butane-2,3-dione Monoximate and 4-chlorophenoxide

등록일
2008년 2월 14일 13시 29분 06초
접수번호
1376
발표코드
32P235포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
금 <발표Ⅴ>
발표형식
포스터
발표분야
유기화학
저자 및
공동저자
민세원, 엄익환1
이화여자대학교 화학과,
1이화여자대학교 나노과학부,
A kinetic study is reported for nucleophilic substitution reactions of Y-substituted-phenyl phenyl carbonates (1a-h) with 4-chlorophenoxide and 2,3-butanedione monoximate in 20 mol % DMSO at 25.0 oC. The Hammett plots correlated with σo and σ– constants exhibit highly scattered points. In contrast, the Y-T plots for the same reactions result in better correlation with 4-ClPhO–(r=0.55) and Ox–(r=0.33), indicating that the leaving group departure occurs at the RDS either in a concerted pathway or in an addition-elimination mechanism with the elimination step being the RDS. The Brønsted-type plot for reactions of 1f is linear with βnuc = 0.52 (a concerted mechanism). The plot of log kOx–/k4-ClPhO– vs. pKa of the conjugate acid of the leaving group results in a slope close to zero, indicating that the α-effect in this system is independent of the electronic nature of the substituent Y.

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