Origin of the Base-Dependent Facial Selectivity in Annulation Reactions of Nazarov-Type Reagents with Unsaturated Indolo[2,3-<i>a</i>]quinolizidine Lactams
作者:Carolina Estarellas、Federica Arioli、Maria Pérez、Celeste Are、David Hevia、Elies Molins、F. Javier Luque、Joan Bosch、Mercedes Amat
DOI:10.1002/ejoc.201700610
日期:2017.7.25
selectivity was observed when the reaction was performed in the presence of Cs2CO3, leading to the corresponding trans adducts. This annulation is the key step of an stereocontrolled synthesis of the 17a-carba-analog of the heteroyohimbine alkaloid akuammigine. Theoretical calculations were used to rationalize the facial selectivity of these double Michael addition reactions.
Stereocontrolled Annulations of Indolo[2,3-<i>a</i>]quinolizidine-Derived Lactams with a Silylated Nazarov Reagent: Access to Allo and Epiallo Yohimbine-Type Derivatives
作者:Federica Arioli、Maria Pérez、Celeste Are、Carolina Estarellas、F. Javier Luque、Joan Bosch、Mercedes Amat
DOI:10.1002/chem.201501912
日期:2015.9.14
The facial selectivity of double Michael addition reactions of the silylated Nazarov reagent 4 to unsaturated indolo[2,3‐a]quinolizidine lactams 3 has been studied. Pentacyclic 3‐H/15‐H trans adducts 5 are generated from Nind‐unsubstituted lactams, but the corresponding cis isomers 6 are formed when the indole nitrogen has a tert‐butyloxycarbonyl (Boc) substituent. This reversal in the facial selectivity
已研究了甲硅烷基化的Nazarov试剂4对不饱和吲哚[2,3- a ]喹诺唑烷内酰胺3的两次迈克尔加成反应的面部选择性。五环3-H / 15-H反式加合物5个从产生Ñ IND -未被取代的内酰胺,但相应的顺式的异构体6时的吲哚氮具有形成叔‐丁氧羰基(Boc)取代基。通过理论计算已经合理地消除了环形表面选择性的这种逆转,这表明在立体电子控制下的初始亲核攻击受到了庞大Boc基团的阻碍。五环Nazarov衍生的加合物的合成有用性通过将其转化为异源和Epiallo育亨宾型靶标而得到证明。