Gram-scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles

A series of acyl fluorides was synthesized at 100 mmol scale using phase transfer catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at rt, followed by extraction and distillation. Isolated acyl fluorides (usually 7 g to 20 g) display excellent purity, and can be transformed into sterically hindered amides and esters, when treated with lithium amide bases and alkoxides under mild conditions.

Compositional flexibility in Li-N-H materials: implications for ammonia catalysis and hydrogen storage.

Li-N-H materials, particularly lithium amide and lithium imide, have been explored for use in a variety of energy storage applications in recent years. Compositional variation within the parent lithium imide,...

Intercalates of Bi2Se3 studied in situ by time-resolved powder X-ray diffraction and neutron diffraction

Intercalation of lithium and ammonia into the layered semiconductor Bi2Se3 proceeds via a hyperextended (by > 60 %) ammonia-rich intercalate, to eventually produce a layered compound with lithium amide intercalated...

Chiral lithium amide mediated desymmetrization of 3-substituted cyclobutanone

A practical approach to access enantioenriched cyclobutenes was developed via a chiral lithium amide mediated deprotonation of 3-substituted cyclobutanones. Further elaborations led to stereoselective assembly of tricyclic skeletons.

Lithium-mediated Ferration of Fluoroarenes

While fluoroaryl fragments are ubiquitous in many pharmaceuticals, the deprotonation of fluoroarenes using organolithium bases constitutes an important challenge in polar organometallic chemistry. This has been widely attributed to the low stability of the in situ generated aryl lithium intermediates that even at –78 °C can undergo unwanted side reactions. Herein, pairing lithium amide LiHMDS (HMDS = N{SiMe3}2) with FeII(HMDS)2 enables the selective deprotonation at room temperature of pentafluorobenzene and 1,3,5-trifluorobenzene via the mixed-metal base [(dioxane)LiFe(HMDS)3] (1) (dioxane = 1,4-dioxane). Structural elucidation of the organometallic intermediates [(dioxane)Li(HMDS)2Fe(ArF)] (ArF = C6F5, 2; 1,3,5-F3-C6H2, 3) prior electrophilic interception demonstrates that these deprotonations are actually ferrations, with Fe occupying the position previously filled by a hydrogen atom. Notwithstanding, the presence of lithium is essential for the reactions to take place as Fe II (HMDS)2 on its own is completely inert towards the metallation of these substrates. Interestingly 2 and 3 are thermally stable and they do not undergo benzyne formation via LiF elimination.

Intercalates of Bi2Se3 Studied in Situ by Time-Resolved Powder X-ray Diffraction and Neutron Diffraction

<div>Intercalation of lithium and ammonia into the layered semiconductor Bi2Se3 proceeds via a</div><div>hyperextended (by > 60 %) ammonia-rich intercalate, to eventually produce a layered compound</div><div>with lithium amide intercalated between the bismuth selenide layers which offer scope for further</div><div>chemical manipulation.</div>

Intercalates of Bi2Se3 Studied in Situ by Time-Resolved Powder X-ray Diffraction and Neutron Diffraction

<div>Intercalation of lithium and ammonia into the layered semiconductor Bi2Se3 proceeds via a</div><div>hyperextended (by > 60 %) ammonia-rich intercalate, to eventually produce a layered compound</div><div>with lithium amide intercalated between the bismuth selenide layers which offer scope for further</div><div>chemical manipulation.</div>