27653-95-8Relevant academic research and scientific papers
Improved Synthesis of MediPhos Ligands and Their Use in the Pd-Catalyzed Enantioselective N-Allylation of Glycine Esters
Albat, Dominik,Neud?rfl, J?rg-Martin,Reiher, Martin,Schmalz, Hans-Günther
supporting information, p. 4237 - 4242 (2021/08/24)
A new class of chiral C2-symmetric diphosphines (MediPhos) was recently shown to give superior results in the Pd-catalyzed asymmetric N-allylation of amino acid esters. We here describe a new, improved protocol for the preparation of such ligands through bidirectional SN2-coupling of a tartrate-derived ditosylate with 6-alkyl-2-bromophenols followed by double lithiation/phosphanylation. This method gave access to a series of nine ligands with branched alkyl substituents, which were benchmarked in the enantioselective Pd-catalyzed N-allylation of tert-butyl glycinate with racemic (E)-2,8-dimethylnona-5-en-4-yl methyl carbonate (up to 95 % ee). In addition, the analogous transformation of tert-butyl glycinate with methyl (E)-nona-5-en-4-yl carbonate was optimized. The obtained allylic amines were then used in the stereoselective synthesis of the conformationally restricted proline-derived dipeptide analogs ProM-17 and ProM-21.
Visible-light driven synthesis of polycyclic benzo[: D] [1,3]oxazocine from 2-aminochalcone
Chen, Junhan,Gao, Yu-Qi,He, Yu-Peng,Hou, Yi,Li, Ruoxin,Xie, Weiqing,Zhang, Sheng-Yong,Zhu, Liming
supporting information, p. 6739 - 6742 (2020/07/13)
Herein, we report a tandem cycloisomerization/nucleophilic addition/cyclization of 2-amino chalcone with bifunctional nucleophiles driven by visible light. This cascade process is realized by the irradiation of a blue LED at room temperature, which provides a concise route to structurally diverse benzo[d][1,3]oxazocine scaffolds. Mechanistic studies show that the reaction is initiated with the E to Z isomerization of a C-C double bond upon the irradiation of visible light, followed by cyclization/rearomatization to generate a transient quinolinium intermediate, which is trapped by the nucleophile and cyclized to produce the polycyclic benzo[d][1,3]oxazocine.
Conversion of conjugated enones into enantiomerically pure β-hydroxy ketones or 1,3-diols - Samarium(II) bromide reductions of protected α,β-dihydroxy ketones
Zoerb, Andreas,Brueckner, Reinhard
experimental part, p. 4785 - 4801 (2010/10/21)
Asymmetric dihydroxylations of α,β-unsaturated ketones in the presence of Sharpless' AD mix-β delivered α,β-dihydroxy ketones or, if phenylboronic acid was present, the corresponding phenylboronates. The Cα-O bonds of these species were removed
Highly substituted tetrahydropyrones from hetero-Diels-Alder reactions of 2-alkenals with stereochemical induction from chiral dienes
Ruijter, Eelco,Schueltingkemper, Heike,Wessjohann, Ludger A.
, p. 2820 - 2823 (2007/10/03)
(Chemical Equation Presented) A new method for the stereoselective synthesis of libraries of 2,3,5-trisubstituted tetrahydro-γ-pyrones and the corresponding tetrahydropyran-4-ols is reported. Dienes with a chiral moiety at position 5 were synthesized star
