Synthesis and reactivity of conformationally locked alpha-aminoorganostannanes and alpha-aminoorganolithiums. Discovery of a surprising configurational requirement for transmetalation.
Synthesis and reactivity of conformationally locked alpha-aminoorganostannanes and alpha-aminoorganolithiums. Discovery of a surprising configurational requirement for transmetalation.
复制标题
构象锁定的α-氨基有机锡烷和α-氨基有机锂的合成和反应性。
DOI：
10.1021/ol005770u
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发表时间：
2000
期刊：
影响因子：
5.2
通讯作者：
Gawley,RE
中科院分区：
文献类型：
--
作者：
Chambournier,G;Gawley,RE
研究了被4-叔丁基取代基构象锁定的2-三丁基锡基-N-甲基哌啶的易位反应(锡、−、锂交换)和与亲电试剂的反应。当锡是赤道时，转金属反应顺利进行，与羰基亲电试剂的反应也是如此。烷基卤化物似乎经历了单电子转移反应，提供了非选择性的烷基化产物，以及自由基歧化产物。令人惊讶的是，轴向取向的锡未能转金属，这表明氮孤对和碳−锡键之间的向斜关系是转金属的必要条件。
2-Tributylstannyl-N-methylpiperidines that are conformationally locked by a 4-tert-butyl substituent were evaluated in transmetalations (Sn−Li exchange) and reactions with electrophiles. When the tin is equatorial, transmetalation occurs smoothly as does reaction with carbonyl electrophiles. Alkyl halides seem to undergo single electron transfer reactions, affording nonselective alkylation products, along with products of radical disproportionation. In a surprise, an axially oriented tin failed to transmetalate, suggesting that a synclinal relationship between the nitrogen lone pair and the carbon−tin bond is a requirement for transmetalation.