RESUMO
The extensively developed ene-type enantioselective cycloisomerization of classical 1,n-enynes provides an efficient approach to chiral cyclic 1,4-dienes. In contrast, the catalytic asymmetric heteroarenyne (heteroarene-alkyne) cycloisomerization involving the dearomative transformation of endocyclic aromatic C=C bonds remains unknown. Herein, we communicate a PdH-catalyzed enantioselective heteroarenyne cycloisomerization reaction of alkyne-tethered indole substrates (formal 1,5- and 1,6-enynes). Based on this strategy, a variety of structurally diverse chiral spiro and fused indoline derivatives bearing quaternary stereocenters and exocyclic C=C bonds are afforded in moderate to excellent yields and excellent enantioselectivities (up to 98 % ee). The classical ene-type enantioselective 1,5-enyne cycloisomerization of N-vinylpropiolamides is also developed to afford chiral 2-pyrrolones in good to excellent ee values.
RESUMO
At present, little is known about the influence of mesenchymal stem cell (MSC) transplantation on connexin43 (Cx43) and connexin45 (Cx45) remodeling in the ischemic heart. In this study, we investigated the effect of MSC transplantation on Cx43 and Cx45 remodeling in the ischemic heart. Wistar rats were subjected to left anterior descending artery ligation to induce myocardial infarction (MI) and then randomly allocated to receive an intramyocardial injection of PBS (MI group) or 5-azacytidine-induced MSCs (MSCs group). Histological examination and western blotting were performed 4 weeks after cell transplantation. We found that the MSCs exhibited plasticity by differentiating into cardiomyocyte-like cells. Gap junction remodeling after MI was characterized by a decrease in Cx43 expression and an increase in Cx45 expression. MSC transplantation modulated the MI-induced abnormalities by up-regulating Cx43 and down-regulating Cx45 expression. MSCs exhibited plasticity by differentiating into cardiomyocyte-like cells and modulated abnormal Cx43 and Cx45 remodeling following MI.
