A Samarium(II)-Mediated, Stereoselective Cyclization for the Synthesis of Azaspirocycles
作者:Giuditta Guazzelli、Lorna A. Duffy、David J. Procter
DOI:10.1021/ol8017209
日期:2008.10.2
Unsaturated keto-lactams undergo sequential conjugate reduction-aldol cyclization on treatment with SmI 2 to give syn-spirocyclic pyrrolidinones and piperidinones containing vicinal, fully substituted stereocenters with complete diastereocontrol. The substituent on nitrogen and the lactam ring size have a marked impact on the efficiency of the spirocyclization.
Utilization of Cyclic Amides as Masked Aldehyde Equivalents in Reductive Amination Reactions
作者:Robin J. Prince、Fang Gao、Jessica E. Pazienza、Isaac E. Marx、Jurgen Schulz、Brian T. Hopkins
DOI:10.1021/acs.joc.9b00816
日期:2019.6.21
sizes was demonstrated through the formation of a range of differentiated diamine products. Furthermore, this methodology was expanded to include N-aryl pyrrolidinone substrates with an enantiopure ester group at the 5-position, and α-amino piperidinones were prepared with complete retention of stereochemical information. The development of this chemistry has enabled the consideration of lactams as useful
Synthesis of Spirocyclic Pyrazolones by Oxidative C–N Bond Formation
作者:Javier Agejas、Laura Ortega
DOI:10.1021/acs.joc.5b00796
日期:2015.6.19
The two-step synthesis of spirocyclic pyrazolone derivatives from simple and commercially available reagents is described. The unusual reaction of 1,3-dicarbonyls with hydrazines and an iodine-mediated oxidative carbon–nitrogen bond formation, joined in a two-step, one-pot reaction, allows the straightforward synthesis of these spirocycles.
By using cheap and innocuous sodiumchlorite, a series of tertiary amines have been oxidized to the corresponding lactams with good selectivity and high yield. In this method, neither transition-metal catalyst nor oxidant was used. In the oxidation step, the pH of the sodiumchlorite was precisely adjusted to pH around 6 using CO2, such pH is a compromise between oxidative properties, chemical stability
通过使用廉价、无害的亚氯酸钠,一系列叔胺被氧化成相应的内酰胺,具有良好的选择性和高收率。在该方法中,既不使用过渡金属催化剂,也不使用氧化剂。在氧化步骤中,使用 CO 2将亚氯酸钠的 pH 值精确调节到 6 左右,这样的 pH 值是氧化特性、化学稳定性和不需要的沉淀之间的折衷。此外,缓冲盐不是必需的,这使得这种氧化反应可以在安全和环境友好的条件下进行。
Catalytic Hydrogenation of Carboxamides and Esters by Well-Defined Cp*Ru Complexes Bearing a Protic Amine Ligand
A novel catalytic method for the straightforward hydrogenation of carboxamides and esters to primary alcohols has been developed. Chiral modification in the ligand sphere of the well-defined Cp*Ru catalyst molecule opens up a new possibility for the development of an enantioselective hydrogenation of racemic substrates via dynamic kinetic resolution.