Enantioselective Mannich reaction of γ-malonate-substituted α,β-unsaturated esters with N-Boc imines catalyzed by chiral bifunctional thiourea-phosphonium salts
作者:Jiaxing Zhang、Gang Zhao
DOI:10.1016/j.tet.2018.12.052
日期:2019.3
A novel enantioselective Mannichreaction of γ-malonate-substituted α, β-unsaturated esters with N-protected arylaldimines was realized by using asymmetric phase-transfer catalysis (APTC). With amino acid-derived bifunctional thiourea-phosphonium salts as a catalyst, a series of enantio-enriched Mannich products could be synthesized under very mild and simple reaction conditions with high yields and
A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michaeladdition of acetylacetone to nitroolefins and the Michaeladdition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines
Stereoselective Organocatalyzed Synthesis of α-Fluorinated β-Amino Thioesters and Their Application in Peptide Synthesis
作者:Elena Cosimi、Oliver D. Engl、Jakub Saadi、Marc-Olivier Ebert、Helma Wennemers
DOI:10.1002/anie.201607146
日期:2016.10.10
β‐amino thioesters were obtained in high yields and stereoselectivities by organocatalyzed addition reactions of α‐fluorinated monothiomalonates (F‐MTMs) to N‐Cbz‐ and N‐Boc‐protected imines. The transformation requires catalyst loadings of only 1 mol % and proceeds under mild reaction conditions. The obtained addition products were readily used for coupling‐reagent‐free peptidesynthesis in solution
Asymmetric Disulfonimide-Catalyzed Synthesis of δ-Amino-β-Ketoester Derivatives by Vinylogous Mukaiyama-Mannich Reactions
作者:Qinggang Wang、Manuel van Gemmeren、Benjamin List
DOI:10.1002/anie.201407532
日期:2014.12.1
organocatalytic asymmetricsynthesis of δ‐amino‐β‐ketoester derivatives has been developed. A chiral disulfonimide (DSI) serves as a highly efficient precatalyst for a vinylogous Mukaiyama–Mannich reaction of readily available dioxinone‐derived silyloxydienes with N‐Boc‐protected imines, delivering products in excellent yields and enantioselectivities. The synthetic utility of this reaction is illustrated
A direct catalytic asymmetric vinylogous Mannich-typereaction has been disclosed in good yield, excellent regio-, diastereo- and enantioselectivity. The key to control the regioselectivity is the combination of a bulky N-acylpyrazole and a bulky bisphosphine ligand. The catalytic system was extended to a bisvinylogous Mannich-typereaction by changing the ligand. The synthetic utility of the vinylogous