Asymmetric
total syntheses of naphthylisoquinoline alkaloids with
a (P)-configuration are described. An atroposelective
Suzuki–Miyaura reaction between naphthyl pinacol boronate and
an aryl iodide bearing an (S)-2-(N-acetylamino)propyl group at the ortho-position
using Pd(OAc)2 in the presence of SPhos and Ba(OH)2 provided the (P)-selective biaryl product
as the major product without any external chiral sources. This biaryl
product was converted into naphthylisoquinoline alkaloids with a (P)-configuration via stereoselective construction of the
isoquinoline framework with the appropriate oxidation state and stereochemistry.
Cyanide as a Powerful Catalyst for Facile Preparation of 2-Substituted Benzoxazoles via Aerobic Oxidation. -A more efficient and scalable synthesis of benzoxazoles from the Schiff bases (I) and (III) is developed tolerating several functional groups. A one-pot procedure is also developed with slightly lower yields. -(CHO, Y. H.; LEE, C.-Y.; HA, D.-C.; CHEON*, C.-H.; Adv. Synth. Catal. 354 (2012) 16, 2992-2996, http://dx.
Enantioselective Synthesis of -Arylamines via Chiral Phosphoric Acid-Catalyzed Asymmetric Reductive Amination. -A novel method for the synthesis of chiral -aryl amines (III) is achieved by Hantzsch ester promoted enantioselective reductive amination of benzyl methyl ketones with anisidine in the presence of a BINOL derived phosphonic acid catalyst. This transformation is applicable to gram-scale reactions, and the catalyst loading can be reduced to 1 mol% without sacrificing any catalytic efficacy. Direct oxidative cyclization of product (IIId) results in the unexpected formation of the spiro compound (IV). -(KIM, K.-H.; LEE, C.-Y.; CHEON*, C.-H.; J. Org. Chem. 80 (2015) 12, 6367-6374, http://dx.doi.org/10.1021/acs.joc.5b00812 ; Dep. Chem., Korea Univ., Seoul 136-701, S. Korea; Eng.) -Mais 44-087
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