Ligand-Free Pd-Catalyzed Synthesis of 3-Allylbenzofurans by Merging Decarboxylative Allylation and Nucleophilic Cyclization.

A new single Pd-catalyzed decarboxylative allylation-nucleophilic cyclization relay is reported by using α-alkynyl arylols and vinylethylene carbonates (or vinyl carbamates), and a wide range of 3-allyl benzofurans with generally good yields were stereoselectively synthesized under mild conditions, among which the complete stereoselectivity of some cases was also observed. Notably, the present catalysts can tolerate air conditions without any ligand, additive, or base, opening new avenues to build up oxa-heterocycle frameworks through catalytic difunctionalization of internal alkynes.

Synthesis of Diastereoenriched 1-Indanones via Double-Base Cooperatively Promoted 1,4-Oxo-Migration/Cyclization of ß-Alkynyl Ketones.

A double-base copromoted 1,4-oxo-migration/cyclization cascade of ß-alkynyl ketones was reported, enabling to form a range of functionalized 1-indanones with moderate to good yields and high diastereoselectivity in the presence of t-BuOK as a Brønsted base and N,N'-dimethylethanediamine (DMEDA) as a Lewis base. Some of these 1-indanones were successfully transformed into 2-haloethyl benzoates with one all-carbon quaternary stereocenter by 1,2-dichloroethane (DCE) or 1,2-dibromoethane (DBE) as both a reactant and a reaction media. This method also features high atomic utilization (100%), high diastereoselectivity, and mild reaction conditions.

Completely Stereoselective Synthesis of Sulfonated 1,3-Dihydroisobenzofurans via Radical Multicomponent Reactions.

Two types of new oxidant-free radical multicomponent reactions of ß-alkynyl ketones, aryldiazonium salts, and DABCO·(SO2)2 (DABSO) were established, leading to the tunable generation of two class of sulfonated 1,3-dihydroisobenzofurans with moderate to good yields and complete stereoselectivity under the mild conditions. The radical-induced scission/recombination of the C(sp3)-C(sp3) bond enabled direct 1,8-halosulfonylation of ß-alkynyl ketones, giving 1,3-dimethylene-substituted (1Z,3Z)-1,3-dihydroisobenzofurans with substituent diversity by p-nitrobenzyl bromide (PNBB) or p-nitrobenzyl chloride (PNBC) as the halo source. Fine-tuning substituents to strong electron-withdrawing ones, such as nitro, cyano, and trifluoromethyl, linked to aryldiazonium tetrafluoroborates allowed a different annulation/1,5-azosulfonylation process to access sulfonated (Z)-1,3-dihydroisobenzofurans with one quaternary carbon-amino functionality.

Generation of 1,3-Dimethylene-Substituted Isobenzofurans via Pd(II)-Catalyzed Selective Oxo-cyclization/SO2 Insertion Cascade of ß-Alkynyl Ketones.

A new palladium(II)-catalyzed cyclization-radical addition cascade enables the direct construction of 1,3-dimethylene-substituted isobenzofuran derivatives containing a vinyl aryl sulfone unit in good yields by treating with ß-alkynyl ketones, aryl diazonium salts, and DABCO·(SO2)2. The oxidant-free multicomponent reaction features good substrate scope and functional group tolerance, which proceeds through a sequence of Heck coupling, oxo-cyclization, and SO2 insertion.

An alternative technique for Descemet's membrane detachment following phacoemulsification: case report and review of literature.

BACKGROUND: Descemet's membrane detachment (DMD) is one of the most serious complications of modern cataract surgery. We present an alternative technique for management of DMD with a review of the literature on current strategies for the treatment of DMD. CASE PRESENTATION: A 74-year-old woman developed DMD after phacoemulsification and failed the first descemetopexy with air tamponade. An alternative method was used to drain the pre-descematic fluid and reposition the detached Descemet's membrane in this rare case. This technique involved completely filling the anterior chamber with an intracameral air injection, followed by using a 23-gauge needle to puncture the peripheral cornea to drain the pre-descematic fluid. The Descemet's membrane was completely reattached to the stroma during the follow-up. CONCLUSIONS: Drainage of pre-descematic fluid combined with intracameral air tamponading was used as an alternative surgical option for the management of this severe case of DMD.

Involvement of PI3K/Akt pathway in TGF-beta2-mediated epithelial mesenchymal transition in human lens epithelial cells.

BACKGROUND: Epithelial mesenchymal transition (EMT) of postoperative remnants of lens epithelial cells (LECs) can lead to posterior capsule opacification. This study was designed to determine the effect of signaling pathways that contribute to TGF-beta2-mediated EMT in human lens epithelial B-3 cells (HLEB-3 cells). METHODS: The HLEB-3 cells were cultured and stimulated with TGF-beta2 at different concentrations for an indicated time. The effect of TGF-beta2 on cell cycle distribution was measured by flow cytometry. Western blot and immunofluorescence were used to analyze changes in connexin 43, fibronectin, desmin and integrin beta(1) protein expression associated with EMT in HLEB-3 cells. Activation of phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways was also detected by Western blot. RESULTS: The cell cycle progression of HLEB-3 cells was limited, and the cells underwent morphological alteration after treatment with TGF-beta2. Stimulation of HLEB-3 cells with TGF-beta(2) suppressed connexin 43 protein expression, increased fibronectin, desmin and integrin beta1 protein expression. TGF-beta2 activated PI3K/Akt in a time-dependent manner, but not extracellular signal-regulated kinase and p38 MAPK. The activation of PI3K/Akt was necessary for the TGF-beta(2)-stimulated downregulation of connexin 43, which in turn was necessary for TGF-beta2-induced EMT in HLEB-3 cells. CONCLUSIONS: TGF-beta(2) is a potent growth factor for LEC EMT. TGF-beta(2)-induced EMT in LECs is mediated by the downregulation of connexin 43, which is regulated through the PI3K/Akt pathway.

[Combined surgery for cataract and glaucoma: phacoemulsification, foldable intraocular lens implantation and viscocanalostomy].

OBJECTIVE: To assess the outcome of phacoemulsification-intraocular lens (IOL) implantation combined with viscocanalostomy (P-C group), compared with that of phacoemulsification-IOL implantation combined with trabeculectomy (P-T group). METHODS: Combined phacoemulsification with corneal incision, foldable intraocular lens implantation and viscocanalostomy was performed in 21 eyes of 19 cataract patients with primary open-angle glaucoma. All patients were followed up for 3 - 6 months. RESULT: Intraocular pressure (IOP) was significantly lower in both P-C group and P-T group (P=0.000). There was no statistically significant difference between two groups. Visual outcome was similar in both groups. Complications of P-C group included Descemet's membrane puncture in 2 eyes, Schlemm's tube puncture in 2 eyes and IOP spikes in 3 eyes (at 24 hours postoperatively). The P-C group experienced significantly less inflammation than the P-T group. CONCLUSION: Phacoemulsification-IOL implantation combined with viscocanalostomy is a safe and effective surgery, with lower complicatin rate and easier ambulatory care.