The use of nonactivated iminodienophiles in the stereoselective aza-Diels–Alder reaction
作者:Anna Trifonova、Pher G Andersson
DOI:10.1016/j.tetasy.2003.12.011
日期:2004.2
This paper describes the preparation of nitrogen-containing bicycles by the aza-Diels–Alder reaction of nonactivated iminodienophiles and cyclopentadiene. Readily available starting materials such as (S)-(−)-lactate and l-amino acids were used for the preparation of chiral aldehydes with high enantiomeric excess. The improved oxidation procedure by Dess–Martin periodinane was employed for the synthesis
本文介绍了非活化亚氨基二烯和环戊二烯的aza-Diels-Alder反应制备含氮自行车的方法。易于获得的原料,例如(S)-(-)-乳酸酯和1-氨基酸被用于制备具有高对映体过量的手性醛。用Dess-Martin高碘烷改进的氧化程序合成了由L-丙氨酸衍生的邻苯二甲酰亚胺保护的醛14,该醛很难通过其他方法以高对映体的形式获得。还研究了不同的路易斯酸对aza-Diels-Alder反应的立体选择性的影响:发现结合使用BF 3 ·Et 2环加成反应中的O和TFA导致由14制备的亚胺完全外消旋化,而使用TiCl 4可使环加成产物17a和17b具有高对映选择性(90%)。