155852-53-2Relevant academic research and scientific papers
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
supporting information, p. 242 - 246 (2021/01/13)
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
Activation of carboxylic acids as their active esters by means of tert-butyl 3-(3,4-dihydrobenzotriazine-4-on)yl carbonate
Basel, Yochai,Hassner, Alfred
, p. 2529 - 2533 (2007/10/03)
Carboxylic acids were activated in the presence of DMAP with tert-butyl carbonates (BOC-OX) 1, which were prepared in situ by reaction of X-OH and di-tert-butyl dicarbonate (BOC2O). The most efficient active carbonate proved to be tert-butyl 3-(3,4-dihydrobenzotriazine-4-on)yl carbonate 1a, leading to efficient formation of benzotriazinonyl esters 3 and 6, which are intermediates in reactions with primary and secondary amines to afford amides or peptides in good yield. By-products in the formation of 3 or 6 are the environmentally safe tert-BuOH and CO2. The hindered amino acid AIB also forms a dipeptide in good yield.
