Stereocontrol of Intramolecular Diels−Alder Reactions: Synthetic Studies and Transition Structure Modeling with C5-Substituted 1,3,8-Nonatrienes and Nonadienynes
作者:Craig I. Turner、Rachel M. Williamson、Michael N. Paddon-Row、Michael S. Sherburn
DOI:10.1021/jo015516v
日期:2001.6.1
An investigation into the endo/exo selectivity and pi-diastereofacial selectivity of ester-tethered intramolecular Diels-Alder reactions is reported. High levels of exo selectivity are realized with terminally substituted dienophiles, and high lk pi-diastereofacial selectivities are induced by the presence of a bulky dioxolanyl substituent at the allylic position of the tether. Precursors 19S, 20S
报道了对酯系分子内Diels-Alder反应的内/外选择性和π-非硬脂基选择性的研究。末端取代的亲二烯体可实现高水平的exo选择性,并且在系链的烯丙基位置存在庞大的二氧戊环取代基,可诱导高水平的pi-非硬脂基表面选择性。易于从葡萄糖制备的前体19S,20S和21S,在110℃下热解后,以对映体纯净形式,以高收率提供可预测的立体化学的致密功能化的双环内酯,具有可预测的立体化学。B3LYP/ 6-31G(d)理论提供了过渡结构的良好描述这些反应并了解主要环加合物的形成。