Herein,
we report a transition-metal-free [4 + 1] cyclization pathway
from difluorocarbene and ortho-amino aryl alkynone,
rendering an effective and universal strategy for the construction
of 3-alkenyl-2-oxindoles. Our strategy starts from cheap and accessible ortho-amino aryl alkynone instead of the direct indole skeleton;
moreover, in situ generated difluorocarbene from commercially available
halogenated difluoroalkylative reagents enables the cleavage of a
C–N bond and formation of new C–N bonds and C–C
bonds.
Tetracoordinate boron species have emerged as radical precursors via deboronation by photo-induced single electron transfer (SET) pathway. These reactions usually produce an alkyl radical and boron-bound species, and the valuable boron species are always discarded as a by-product. Given the importance of boron species, it will be very attractive if the two parts could be incorporated into the eventual products. Herein we report a photo-catalyzed strategy in which in situ generated tetracoordinated boron species decomposed into both alkyl radicals and boron species under visible light irradiation, due to the pre-installation of a vinyl group on the aromatic ring, the newly generated alkyl radical attacks the vinyl group while leaving the boron species on ipso-position, then both radical part and boron moiety are safely incorporated into the final product. Tertiary borons, secondary borons, gem-diborons as well as 1,2-diborons, and versatile electrophiles are all well tolerated under this transformation, of note, ortho-, meta- and para-bromostyrenes all demonstrated good capabilities. The reaction portraits high atom economy, broad substrate scope, and diversified valuable products with tertiary or quaternary carbon center generated, with diborons as substrates, Csp2-B and Csp3-B are established simultaneously, which are precious synthetic building blocks in chemical synthesis.
Although practice guidelines recommend surgery for patients with severe chronic ischemic mitral regurgitation (CIMR), they do not specify whether to repair or replace the mitral valve. 436 consecutive patients with severe CIMR were eligible for inclusion in the study, of which 316 (72.5%) underwent mitral valve annuloplasty (MVA) whereas 120 (27.5%) received mitral valve replacement (MVR). At 59 months (interquartile range, 37–85 months) follow-up, though the left ventricle end-diastolic diameter was markedly larger (P = 0.019) in the MVA group than in the MVR group, no significant difference was observed in overall survival, freedom from cardiac death, or avoidance of major adverse cardiac or cerebrovascular events (MACCE). MVA provides better results in freedom from cardiac death in subgroups of age ≥65years and left ventricular ejection fraction (EF) ≥50% (P = 0.014 and P = 0.016, respectively), whereas MVR was associated with a lower risk of MACCE in subgroups of age <65years, EF <50% and left ventricular inferior basal wall motion abnormality (BWMA) (all P < 0.05). In conclusion, MVR is a suitable management of patients with severe CIMR, and it is more favorable to ventricular remodeling. The choice of MVA or MVR should depend on major high-risk clinical factors.
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