Asymmetric Multicomponent Reactions: Diastereoselective Synthesis of Substituted Pyrrolidines and Prolines
作者:Arun K. Ghosh、Sarang Kulkarni、Chun-Xiao Xu、Phillip E. Fanwick
DOI:10.1021/ol061672i
日期:2006.9.1
A novel diastereoselective synthesis of substitutedpyrrolidines has been developed. Asymmetric multicomponentreactions of optically active phenyldihydrofuran, N-tosyl imino ester, and silane reagents in a one-pot operation afforded highlysubstitutedpyrrolidine derivatives diastereoselectively. The reaction is quite efficient and constructed up to three stereogenic centers in a single operation
Synthesis of pseudo-oligosaccharides by a sequence of yne-ene cross metathesis and Diels–Alder reaction
作者:Stephan C. Schürer、Siegfried Blechert
DOI:10.1039/a903208h
日期:——
Various pseudo oligosaccharides were prepared by a combination of selective yne-ene cross metathesis and DielsâAlder reaction from readily available monosaccharide building blocks.
Gold-Catalyzed Mannich Addition Reactions of 1,3-Dicarbonyl Compounds with<i>N</i>-Protected Imines
作者:Manuela Delgado-Rebollo、Rocio Moreno、Manuel R. Fructos、Auxiliadora Prieto
DOI:10.1002/ejoc.201201252
日期:2013.1
The first (N-heterocyclic carbene)AuI-catalyzed Mannichadditionreactions of N-protected imines with different 1,3-dicarbonylcompounds are described. IPrAuNTf2 was proven to be an efficient catalyst for the reactions of β-keto esters and 1,3-diketones with N-sulfonylimines to afford the desired β-amino carbonyl compounds in good yields under very mild conditions.
A Practical and Efficient Total Synthesis of Potent Insulinotropic (2S,3R,4S)-4-Hydroxyisoleucine through a Chiral N-Protected γ-Keto-α-aminoester
作者:Sandra De Lamo Marin、Cédric Catala、Sreekantha Ratna Kumar、Alain Valleix、Alain Wagner、Charles Mioskowski
DOI:10.1002/ejoc.201000378
日期:2010.7
(2S,3R,4S)-4-Hydroxyisoleucine, which exhibits remarkable insulinotropic activity, is expected to be a potent drug to treat type II diabetes. We propose herein a four-step synthesis of the enantiopure natural product on the basis of successive Mannich condensation, catalytic epimerization, N-para-methoxyphenyl deprotection, and diastereoselective reduction. This compact economical and scalable sequence
(2S,3R,4S)-4-羟基异亮氨酸具有显着的促胰岛素活性,有望成为治疗 II 型糖尿病的有效药物。我们在此提出基于连续曼尼希缩合、催化差向异构化、N-对甲氧基苯基脱保护和非对映选择性还原的四步合成对映纯天然产物。这种紧凑经济且可扩展的序列能够完美地控制三个连续的手性中心。它不涉及任何色谱纯化,在我们优化的条件下以 >99% de、>99% ee 和 22% 的总收率获得所需化合物。
Application of Photoclick Chemistry for the Synthesis of Pyrazoles via 1,3-Dipolar Cycloaddition between Alkynes and Nitrilimines Generated In Situ
作者:Richard Remy、Christian G. Bochet
DOI:10.1002/ejoc.201701225
日期:2018.1.23
The photolysis of tetrazoles leads to the extrusion of dinitrogen and forms a reactive nitrile imine intermediate. The latter can then react in situ with alkynes in a [3+2] cycloaddition providing pyrazoles. Some reactivity trends were identified, such as a preference for electron‐poor alkynes. On the tetrazole part, there is a clear preference for either aromatic or conjugated substituents.