Total Syntheses of (−)‐Huperzine Q and (+)‐Lycopladines B and C

Abstract

Utilizing a late-stage enamine bromofunctionalization strategy, the twelve-step total synthesis of (À)-huperzine Q was accomplished. Furthermore, the first total syntheses of (+)-lycopladines B and C are described. An unprecedented X-ray crystal structure of an unusual epoxyamine intermediate is also reported, and the synthetic application of this intermediate in natural product synthesis is demonstrated.

Brønsted-Acid-Catalyzed Intramolecular Carbonyl–Olefin Reactions: Interrupted Metathesis vs Carbonyl-Ene Reaction

“…This indicates that the initial buildup of the experimentally observed diene species (22, Scheme 1B) is driven by kinetic preference. Furthermore, species 15 is the key intermediate that connects the substrate and transient diene product (18) through the CE reaction followed by dehydration. The CE reaction, therefore, appears as a plausible pathway for the activation of CO substrates by TfOH.…”

“…Carbonyl–olefin metathesis ( COM ), − an analogue of the well-developed olefin metathesis reaction, is an evolving synthetic method for constructing carbon–carbon bonds from simple starting materials. − The routine practice of COM was limited prior to reports of a bicyclic hydrazine catalyst that effects the transformation catalytically. More recently, Schindler and co-workers described a general catalytic approach involving earth-abundant Lewis acid ( LA ) catalysts (typically FeCl 3 ), allowing catalytic intramolecular COM reactions involving aliphatic and aromatic substrates.…”

An Amphiphilic Molecule‐Regulated Core‐Shell‐Solvation Electrolyte for Li‐Metal Batteries at Ultra‐Low Temperature

“…Therefore, several promising electrolyte strategies have been explored to construct inorganic‐rich SEI, including additive‐assisted electrolytes, [11, 12] liquefied gas electrolytes, [13, 14] high‐concentration electrolytes (HCEs), [15–17] and localized high‐concentration electrolytes (LHCEs) [18, 19] . These performance‐enhancement are essentially achieved by tuning the components of the Li + inner solvation sheath, which dominates the SEI compositions and thereby plays a decisive role in regulating the migration of Li + through SEI and the deposition behavior of Li [20] …”

“…[18,19] These performance-enhancement are essentially achieved by tuning the components of the Li + inner solvation sheath, which dominates the SEI compositions and thereby plays a decisive role in regulating the migration of Li + through SEI and the deposition behavior of Li. [20] In particular, the HCEs successfully reduce the solvent molecules while extensively recruit anions within the Li + inner solvation sheath, leading to a high oxidative stability as well as an anion-derived inorganic-rich SEI with better Li cyclability. To compensate the high cost and viscosity associated with HCEs, a whole family of non-solvating hydrofluoroethers, such as 1,1,2,2-tetrafluoroethyl-2,2,3,3tetrafluoropropylether (TTE) and bis(2,2,2trifluoroethyl)ether (BTFE), was introduced to dilute the high concentration while maintaining locally anion-rich solvation structure as well as their merits (such as high oxidative stability, Al corrosion prevention, and good Li compatibility), which is termed as LHCEs.…”