The left hand claps the right: Highly enantioselective isomerization of racemic α‐substituted alkynoates into nonracemic trisubstituted allenoates was achieved through the catalytic dynamic kinetic resolution mediated by bifunctional benzothiadiazine. This reaction proceeded with good conversion and high enantioselectivity to give the desired allenoates in good yields without recovering the significant amounts of starting materials.

Rhinacanthus nasutus (L.) KURZ (Acanthaceae) is a shrub widely distributed in South China and India. In this study, the antiproliferative activity of the ethanol extract of root and aqueous extract of leaves of R. nasutus, and the supposed active moiety rhinacanthin C was assessed in vitro using the human cervical carcinoma cell line HeLa, its MDR1-overexpressing subline Hvr100-6, human prostate carcinoma PC-3 cells and human bladder carcinoma T24 cells. Rhinacanthin C was chemically synthesized and its content in the R. nasutus extracts was determined by HPLC with a photodiode array detector. The antiproliferative activity of the R. nasutus extracts was also assessed in vivo using sarcoma 180-bearing mice. It was suggested that 1) the in vitro antiproliferative activity of rhinacanthin C was comparable with or slightly weaker than that of 5-FU, 2) rhinacanthin C showed antiproliferative activity for MDR1-overexpressing Hvr100-6 cells, similarly to parent HeLa cells, 3) the in vitro antiproliferative activity of the ethanol extract of root R. nasutus was due to rhinacanthin C, whereas that of the aqueous extract of leaves of R. nasutus was due to constituents other than rhinacanthin C, and 4) both of the R. nasutus extracts showed in vivo antiproliferative activity after oral administration once daily for 14 d.

The asymmetric synthesis of beta-substituted alpha-amino acids with use of iridium-catalyzed allylic substitution was described. The Ir-catalyzed allylic substitution of diphenylimino glycinate with allylic phosphates proceeded smoothly even at 0 degrees C and gave branch products with high enantioselectivity (up to 97% ee), when chiral bidentate phosphite bearing the 2-ethylthioethyl group was employed. In addition, both diastereomers of the branch products were synthesized stereoselectively by simply switching the base employed. These methods were also applied to the asymmetric synthesis of quaternary alpha-amino acids.

No abstract

The Darzens reaction using electron deficient p-substituted benzyltriethylammonium chlorides with aromatic aldehydes afforded 2,3-diaryl epoxides with trans selectivity (>99%) while the corresponding reaction with electron releasing p-substituted benzyltriethylammonium salts gave the epoxides as diastereomeric mixtures. Epoxide formation of p-trifluoromethylbenzylammonium salt, prepared from p-trifluoromethylbenzyl chloride and DABCO, afforded the corresponding 2,3-diaryl epoxide in high yield (>98%).

Catalytic synthesis of indole-3-carboxamides from 2-ethynylanilines and isocyanates was achieved in the presence of a rhodium catalyst through a tandem-type, cyclization-addition sequence. This tandem-type process can be performed under mild reaction conditions, affording 2,3-disubstituted indoles in a one-pot manner generally in good to excellent yields. The broad substrate scope and good functional group compatibility make the method highly efficient and widely applicable, providing a facile and entirely novel route toward variously substituted indole-3-carboxamides.

An asymmetric thia-Michael addition of arylthiols to α,β-unsaturated carboxylic acids using a thiourea catalyst that bears arylboronic acid and tertiary amine moieties is reported.

No abstract