Search

A highly efficient strategy of two different types of nitrogen-rich heterocyclic energetic compounds, featuring a single NH-bridge (–NH–) and a fused ring, was demonstrated by virtue of Dimroth rearrangement reactions using 4-amino-5-nitro-1,2,3-triazole as the precursor. Various nitrogen-rich compounds and their salts were prepared via this transformation and fully characterized using multinuclear NMR spectroscopy, IR, elemental analysis, and single crystal X-ray structuring. Their key properties, such as decomposition temperatures, densities, detonation velocities and pressures, and impact sensitivities, were obtained from theoretical calculations or experimental measurements. With different task-specific explosophores, the representative energetic compounds 6b and 18 exhibit great potential as high performance insensitive energetic materials and organic primary explosives, respectively. This work gives the classic Dimroth rearrangement new vitality to access diversified task-specific energetic materials.

Described herein is a novel and efficient copper-catalyzed oxidative phosphonation of α-tert-hydroxylalkenes. This protocol displays a broad scope with good functional group compatibility and gives efficient access to diverse β-oxophosphine oxides from simple allylic alcohols and H-phosphine oxides. The mechanism is proposed to be an unprecedented three-component radical coupling/fragmentation cascade reaction of α-tert-hydroxylalkenes, HP(O)R1R2 and tert-butyl hydroperoxide (TBHP), in which the excess TBHP acts as not only a radical initiator but also a coupling partner.

An enantioselective total synthesis of the natural chroman-sesquiterpenoid (−)-8-epi-chromazonarol has been accomplished by a unique N2H4·H2O promoted highly diastereo-selective oxa-Michael cyclization to construct the central chroman framework and assemble the unusual C8 stereocenter. The other salient feature of the reported synthesis involves a Stille carbonylative cross-coupling reaction to link the aryl stannane 9 and bicyclic triflate 10.

The construction of the ABC tricyclic skeleton of malabanone A with the required 4 stereocenters was accomplished in a concise route starting from R-carvone. The synthesis featured an intramolecular [3 + 2] cycloaddition reaction to assemble its A ring and an intramolecular Diels-Alder reaction to construct its C ring.

The first asymmetric total synthesis of gymnothelignan L has been accomplished in 14 steps with 11.2% overall yield. The synthetic approach features an anti Evans aldol reaction, a diastereoselective methylation, a Suzuki–Miyaura coupling and a bioinspired desymmetric transannular Friedel–Crafts reaction. Notably, the synthesis further demonstrated the biogenetic pathway that dibenzocyclooctene-type lignans are generated from eupomatilone-type lignans.

An efficient synthesis of complex tetracyclic compounds is developed which relies on a gold(I)-catalyzed tandem 1,2-acyloxy migration/[3 + 2] cycloaddition/Friedel–Crafts type cyclization reaction of linear enynyl esters. The reaction proceeds under extremely mild conditions in good to excellent yields (54%–88%) with a dr value of up to 20 : 1.