University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
Org Lett. 2020 Jun 19;22(12):4721-4725. doi: 10.1021/acs.orglett.0c01523. Epub 2020 May 28.
Racemic γ-substituted allenes undergo enantioselective higher order [8 + 2]-cycloaddition with azaheptafulvenes using a chiral amino acid derived amidophosphine as catalyst, providing the corresponding azaazulenoid cycloadducts with excellent levels of regio-, diastereo-, and enantioselectivities. In this reaction, the activated allylic phosphonium ylide intermediate participates as the C-component of the reaction, in contrast to the conventional reactivity of this type of zwitterionic intermediates as C-components in cycloaddition reactions.
外消旋 γ-取代丙二烯与氮杂庚富烯在由手性氨基酸衍生的酰胺膦作为催化剂的作用下，发生对映选择性的高阶[8 + 2]-环加成反应，生成具有优异区域选择性、非对映选择性和对映选择性的相应氮杂薁环加成产物。在这个反应中，活化的烯丙基磷叶立德中间体作为反应的 C-组分参与，这与这种两性离子中间体在环加成反应中作为 C-组分的常规反应性相反。
