Changmin Xie - Academia.edu (original) (raw)

Papers by Changmin Xie

Synthesis

Herein, we reported a nine-step synthetic route to access the tricyclic core of FR901483, featuri... more Herein, we reported a nine-step synthetic route to access the tricyclic core of FR901483, featuring a key aza-Wacker cyclization step to construct an α-tertiary amine (ATA) in the bridged structure. The aza-Wacker protocol can tolerate both exocyclic and endocyclic double bonds, providing viable access to various bridged bicyclic rings bearing an ATA (e.g., 6-azabicyclo[3.2.1]octane, 7-azabicyclo[3.3.1]nonane, and 7-azabicyclo[4.2.1]nonane) in good to excellent yields. The synthetic studies presented herein enable structural derivatization of FR901483 to further exploit its compelling biological activities.

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

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Tetrahedron, 2018

In this full account, the evolution of a synthetic strategy was detailed from a nitroso-ene cycli... more In this full account, the evolution of a synthetic strategy was detailed from a nitroso-ene cyclization to an aza-Wacker reaction for ring construction in the syntheses of melinonine-E and strychnoxanthine. The aza-Wacker cyclization to form the bridged ring was successfully developed and applied in the first asymmetric syntheses of melinonine-E and strychnoxanthine in 5e6 steps from a readily available chiral lactone. The proposed biogenesis of these two rare b-carbolinium alkaloids was revised based on their absolute configurations. Moreover, the substrate scope of the aza-Wacker cyclization demonstrated its potential for accessing various bridged ring skeletons. The mechanistic investigation established that the profound effect of the N-substituent on the amide was crucial to the success of the cyclization via the tunable amidopalladation pathway.

Tetrahedron Letters, 2017

A concise synthesis of helicascolides A, B and C was achieved in three to five steps from commerc... more A concise synthesis of helicascolides A, B and C was achieved in three to five steps from commercially available materials. The key transformations of the synthesis include an Evans-Metternich anti-aldol reaction of the known b-keto imide 10 and strategic base-mediated one-pot cyclization/alkylation. Based on the new chemical evidence of ring-opening reaction of b-keto ester under biocompatible basic conditions, Krohn's proposal for the biosynthetic relationship between helicascolide A (1) and a naturally co-existing acyclic dienone 4 was suggested in a reverse manner.

Organic Letters, 2018

Procedure for the preparation of 2-(cyclopent-3-en-1-yl)acetic acid (S10) 3 To a solution of S9 (... more Procedure for the preparation of 2-(cyclopent-3-en-1-yl)acetic acid (S10) 3 To a solution of S9 (2.0 g, 17.8 mmol) in CHCl3 (60 mL) was added oxalyl chloride (4.5 g, 35.6 mmol) at room temperature. After stirring at 40 o C for 3 h, the volatile in the reaction mixture was removed under reduced pressure. The residue was dissolved in THF/CH3CN (40 mL/40 mL) and then a solution of TMSCHN2 (2 M in hexane, 19.6 mL) was added via a syringe at 0 o C. The resulting mixture was stirred at room temperature for 12 h and concentrated under reduced pressure. The residue was dissolved in a mixture of 1,6-dioxane (40 mL) and H2O (40 mL), and then AgOAc (0.89 g, 5.3 mmol) was added. The reaction mixture was heated at 60 o C for 2 h and extracted with ethyl acetate (40 mL×3). The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was subjected to purification on silica gel chromatography (PE/EA, 20/1 to 4/1) to afford S10 as pale yellow oil (1.6 g, 71%).

Organic letters, Jul 21, 2017

An organocatalytic cross-aldol reaction of formaldehyde (formalin) with alkyl aldehydes, followed... more An organocatalytic cross-aldol reaction of formaldehyde (formalin) with alkyl aldehydes, followed by the Z-selective Horner-Wadsworth-Emmons (HWE) reaction and immediate lactonization, afforded γ-alkylated pentenolides in good overall yields and excellent enantioselectivities. Based on this scalable sequence, five quinolizidine alkaloids were synthesized in a unified and concise manner. The development of an in situ activation of a tertiary amide to improve the efficiency of the Bischler-Napieraiski (B-N) reaction was also noteworthy due to the generality to sensitive substrates for a variety of target molecules.

ChemInform, 2014

A kinetic resolution of a diol via etherification catalyzed by a chiral phosphoric acid was devel... more A kinetic resolution of a diol via etherification catalyzed by a chiral phosphoric acid was developed and applied in the concise total synthesis of (+)-sacidumlignan D, the antipode of natural sacidumlignan D. A zinc-mediated crotylation of a diarylketone and subsequent lactonization quickly established the carbon framework of this class of tetrahydrofuran lignans.

Frontiers in Chemistry, 2015

Journal of the American Chemical Society

Nature Communications, 2021

Voltage dependent anion channel 2 (VDAC2) is an outer mitochondrial membrane porin known to play ... more Voltage dependent anion channel 2 (VDAC2) is an outer mitochondrial membrane porin known to play a significant role in apoptosis and calcium signaling. Abnormalities in calcium homeostasis often leads to electrical and contractile dysfunction and can cause dilated cardiomyopathy and heart failure. However, the specific role of VDAC2 in intracellular calcium dynamics and cardiac function is not well understood. To elucidate the role of VDAC2 in calcium homeostasis, we generated a cardiac ventricular myocyte-specific developmental deletion of Vdac2 in mice. Our results indicate that loss of VDAC2 in the myocardium causes severe impairment in excitation-contraction coupling by altering both intracellular and mitochondrial calcium signaling. We also observed adverse cardiac remodeling which progressed to severe cardiomyopathy and death. Reintroduction of VDAC2 in 6-week-old knock-out mice partially rescued the cardiomyopathy phenotype. Activation of VDAC2 by efsevin increased cardiac co...