A Novel [3+2] Cycloaddition Approach to Nitrogen Heterocycles via Phosphine-Catalyzed Reactions of 2,3-Butadienoates or 2-Butynoates and Dimethyl Acetylenedicarboxylate with Imines: A Convenient Synthesis of Pentabromopseudilin
摘要:
The reactivity of a new three carbon synthon, generated in situ from the reaction of 2,3-butadienoates or 2-butynoates with an appropriate phosphine as the catalyst, toward the electron deficient imines is described. Triphenylphosphine-catalyzed reaction of-methyl a,3-butadienoate with N-sulfonylimines gave the single [3+2] cycloadduct in excellent yield; tributylphosphine-catalyzed reaction of methyl 2,3-butadienoate or 2-butynoate with N-tosylimines afforded the corresponding [3+2] cycloadduct as the major product along with a small amount of the three components adduct. Aliphatic N-tosylimines gave moderate yield for this reaction. In addition, a new phosphine-catalyzed cyclization reaction of dimethyl acetylenedicarboxylate with N-tosylimines is also described. A:reaction mechanism is proposed. Further elaborations of the cycloaddition products and the synthesis of pentabromopseudilin using this method are exemplified.
摘要 本文报道了在吡啶作为碱存在下使用K 2 S 2 O 8由N- (芳基磺酰基)苄胺合成合成有用的N-芳基磺酰亚胺的温和、操作方便且实用的方法。此外,还报道了通过与邻位取代的苯胺原位生成的N-芳基磺酰亚胺的反应,“一锅法”串联合成药学相关的N-杂环。该方案的主要特点包括使用绿色氧化剂、反应时间短(30 分钟)、免色谱分离、可扩展性和经济性,可提供N-芳基磺酰亚胺,产率高达 96%。虽然据报道使用K 2 S 2 O 8将N-芳基(苄基)胺氧化成N-芳基亚胺是有问题的,但使用K 2 S 2 O 8将N- (芳基磺酰基)苄胺氧化成N-芳基磺酰亚胺已经是有问题的。首次实现。硫酸根阴离子(SO 4 ·− )的双重作用,包括氢原子夺取(HAT)和单电子转移(SET),被认为参与了合理的反应机制。 贝尔斯坦 J. 组织。化学。 2023, 19, 771–777。doi:10.3762/bjoc.19
The first highly efficient double Friedel–Crafts reaction of N-tosyl imines with anisole, phenol, thioanisole and analogues has been developed to produce the corresponding symmetric diarylmethanes and triarylmethanes with high regioselectivity in the presence of a catalytic amount of Bi2(SO4)3–TMSCl at room temperature.
Cu-catalyzed cyanomethylation of imines and α,β-alkenes with acetonitrile and its derivatives
作者:Muhammad Siddique Ahmad、Atique Ahmad
DOI:10.1039/d0ra10693c
日期:——
We describe copper-catalyzed cyanomethylation of imines and α,β-alkenes with a methylnitrile source and provide an efficient route to synthesize arylacrylonitriles and β,γ-unsaturated nitriles. This method tolerates aliphatic and aromatic alkenes substituted with a variety of functional groups such as F, Cl, Br, Me, OMe, tert-Bu, NO2, NH2 and CO2H with good to excellent yields (69–98%). These systems
Highly diastereoselective Mannich-type reaction of titanium enolate derived from 2′-hydroxypropiophenone
作者:Guisheng Deng、Honghua Mo、Jing Luo、Jingyuan Zou
DOI:10.1139/v2012-027
日期:2012.6
N-tosylimines. Noteworthy is the observation that the influence of a second Lewisacid on the Mannich-type reaction based on the titaniumenolate is opposite to that obtained from other titaniumenolates reported. A reasonable mechanism has been proposed to explain the high anti diastereoselectivity and the effect of a second Lewisacid on yield.
A Convenient Route to Enantiopure 3-Aryl-2,3-diaminopropanoic Acids by Diastereoselective Mannich Reaction of Camphor-Based Tricyclic Iminolactone with Imines
A novel and convenient route to the asymmetric synthesis of 2,3-diamino acids via Mannich reaction of iminolactones 1a and 1b with N-protected imines has been achieved in good yields (up to 95%) and high diastereoselectivity (dr: >99:1). Hydrolysis of the Mannich adducts under acidic conditions furnished the desired 3-aryl-2,3-diaminopropanoic acids in good yields (up to 85%) with excellent enantiomeric
Synthesis and Anti-inflammatory Evaluation of 2-Aminobenzaldehydes via Ir(III)-Catalyzed C–H Amidation of Aldimines with Acyl Azides
作者:Saegun Kim、Prashant Chakrasali、Hyo Sun Suh、Neeraj Kumar Mishra、Taeyoung Kim、Sang Hoon Han、Hyung Sik Kim、Byung Mu Lee、Soo Bong Han、In Su Kim
DOI:10.1021/acs.joc.7b01280
日期:2017.7.21
azides as amidation surrogates under cationic iridium(III) catalysis is described. This transformation efficiently provides a range of 2-aminobenzaldehyde derivatives with excellent site selectivity and functional group compatibility. The resulting 2-aminobenzaldehyde framework provides facile access to a range of biologically interesting heterocycles. In addition, all synthetic compounds were screened