Klein Rosalyn, Gawley Robert E
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA.
J Am Chem Soc. 2007 Apr 11;129(14):4126-7. doi: 10.1021/ja0692377. Epub 2007 Mar 16.
The kinetics of tin-lithium exchange in heterocyclic α-aminoorganostannanes have been studied using Sn rapid-injection NMR. By comparison of the observed relative rate constants, the effects of ring size, configuration, and conformation can be discerned. Stannylpyrrolidines transmetalate extremely rapidly, whereas the rate of transmetalation of stannylpiperidines varies from negligible transmetalation to rapid transmetalation. The evidence suggests that only one conformation of -methyl-2-(tributylstannyl)piperidine transmetalates. -Boc stannyl piperidines transmetalate at rates that vary somewhat, due in part to conformational effects.
利用锡快速注射核磁共振技术研究了杂环α-氨基有机锡烷中锡-锂交换的动力学。通过比较观察到的相对速率常数，可以辨别环大小、构型和构象的影响。锡基吡咯烷的金属转移反应极其迅速，而锡基哌啶的金属转移速率从可忽略不计到迅速转移不等。有证据表明，只有一种构型的α-甲基-2-（三丁基锡基）哌啶发生金属转移反应。α-叔丁氧羰基锡基哌啶的金属转移速率有所不同，部分原因是构象效应。
