描述了将硝基乙酸乙酯高度对映选择性地有机催化加至由芥末衍生的N-Boc酮亚胺(Boc =叔丁氧基羰基)中,然后除去硝基的方法。可扩展的反应序列导致标题化合物作为吡咯并吲哚啉生物碱和相关药物的重要中间体,具有优异的收率和对映选择性。已进行了六氢呋喃[2,3- b ]吲哚骨架,螺氨基甲酸酯和吲哚单元的合成,以及AG-041R的正式合成,以证明该方案的合成效用。
A chiral organic base catalyst with halogen-bonding-donor functionality: asymmetric Mannich reactions of malononitrile with <i>N</i>-Boc aldimines and ketimines
A chiral organic basecatalyst with halogen-bonding-donor functionality has been developed. This quinidine-derived acid/basecatalyst smoothly promoted the asymmetricMannichreaction of malononitrile and various N-Boc imines with up to 98% ee. The cooperative interaction with both substrates was responsible for the high activity that allowed a reduction of the catalyst amount to 0.5 mol%.
Highly Enantioselective Addition of Enals to Isatin-Derived Ketimines Catalyzed by N-Heterocyclic Carbenes: Synthesis of Spirocyclic γ-Lactams
作者:Hui Lv、Bhoopendra Tiwari、Junming Mo、Chong Xing、Yonggui Robin Chi
DOI:10.1021/ol302475g
日期:2012.11.2
An N-heterocycliccarbene (NHC)-catalyzed annulation reaction of isatin N-Boc ketimines and enals is developed for the synthesis of spirocyclic oxindole-γ-lactams bearing one quaternary chiral center in good yields and excellent stereoselectivities (up to >20:1 dr and 99% ee).
The Morita-Baylis-Hillman reaction of acrylamide, as an activated alkene, has seen little development due to its low reactivity. We have developed the reaction using isatin derivatives with acrylamide, DABCO as a promoter and phenol as an additive in acetonitrile. The corresponding aza version with acrylate and acrylonitrile has also been developed resulting in high product yields.
Diastereoselective 1,3-Dipolar Cycloadditions of <i>N</i>,<i>N</i>′-Cyclic Azomethine Imines with Iminooxindoles for Access to Oxindole Spiro-<i>N</i>,<i>N</i>-bicyclic Heterocycles
In the presence of CuI, 1,3-dipolarcycloadditions of N,N′-cyclic azomethine imines with iminooxindoles proceeded readily and furnished novel oxindole spiro-N,N-bicyclic heterocycles in moderate to excellent chemical yields with excellent diastereoselectivities.
Organocatalytic asymmetric cyanation of isatin derived N-Boc ketoimines
作者:Yun-Lin Liu、Jian Zhou
DOI:10.1039/c2cc36665g
日期:——
We report the first catalytic asymmetric cyanation of N-Boc ketoimines, which enables highly enantioselective synthesis of oxindole based α-amino nitriles. An unprecedented tandem aza-Wittig/Strecker reaction is also developed, emerging as a promising strategy for the catalytic asymmetric cyanation of ketoimines formed in situ from achiral ketones.