84801-99-0Relevant academic research and scientific papers
Ligand-enabled β-C-H arylation of α-amino acids using a simple and practical auxiliary
Chen, Gang,Shigenari, Toshihiko,Jain, Pankaj,Zhang, Zhipeng,Jin, Zhong,He, Jian,Li, Suhua,Mapelli, Claudio,Miller, Michael M.,Poss, Michael A.,Scola, Paul M.,Yeung, Kap-Sun,Yu, Jin-Quan
supporting information, p. 3338 - 3351 (2015/03/30)
Pd-catalyzed β-C-H functionalizations of carboxylic acid derivatives using an auxiliary as a directing group have been extensively explored in the past decade. In comparison to the most widely used auxiliaries in asymmetric synthesis, the simplicity and practicality of the auxiliaries developed for C-H activation remains to be improved. We previously developed a simple N-methoxyamide auxiliary to direct β-C-H activation, albeit this system was not compatible with carboxylic acids containing α-hydrogen atoms. Herein we report the development of a pyridine-type ligand that overcomes this limitation of the N-methoxyamide auxiliary, leading to a significant improvement of β-arylation of carboxylic acid derivatives, especially α-amino acids. The arylation using this practical auxiliary is applied to the gram-scale syntheses of unnatural amino acids, bioactive molecules, and chiral bis(oxazoline) ligands.
Intramolecular Nucleophilic Acyl Substitution Reactions Mediated by Samarium(II) Iodide: A Convergent Approach to the Preparation of Enantiomerically Enriched 4-Hydroxy Ketones from 3-Iodopropyl Carboxylates
Molander, Gary A.,Shakya, Sagar R.
, p. 3445 - 3452 (2007/10/02)
Intramolecular nucleophilic acyl substitution (I NAS) reactions of substituted δ-iodopropylcarboxylates have been achieved using samarium(II) iodide (SmI2) in the presence of an iron(III) catalyst.Diverse ester starting materials containing stereogenic centers placed in varying postions on the substrates have been converted to acyclic 4-hydroxy ketone derivatives in good yields using this method.No racemization of stereogenic centers α to the carbonyl was observed in any of the reactions examined.Consequently, the method serves as a convenient, high-yield synthesis of functionalized, enantiomerically enriched acyclic ketones possesing stereogenic centers far removed from one another.
