Total Synthesis of (±)-Isocembrene: A Tactic for Both Diene Construction and Macrocycle Formation

Abstract

The total synthesis of (±)-isocembrene 1, a naturally occurring cembrene diterpenoid, has been achieved via a unified, convergent and highly efficient strategy by imploying an intramolecular Stille sp²–sp² macrocyclization as the key step and it presents an ideal opportunity to extend the effectiveness of the tactic for both 1,3-diene construction and macrocycle formation.     

REDUCTION OF BIS(BROMO(MESITYL)-{2,4,6-TRIS[BIS(TRIMETHYLSILYL)METHYL]- PHENYL}SILYL)BUTADIYNE WITH POTASSIUM GRAPHITE: UNEXPECTED FORMATION OF 2-ALLENYL-1-BENZOSILOLE

The reductive debromination of an very crowded bis(bromodiaryl- silyl)butadiyne 2 was performed with potassium graphite to give the corresponding 2-allenyl-1-benzosilole 3 was isolated as a main product.     

Phosphorus-Containing Dendrimers: Synthesis and Properties

Several series of phosphorus-containing dendrimers have been designed to study the variation of their properties, depending on the type, the location (surface, branches, core, and cavities), and the number of functions implied.     

Synthesis of 6-carboxylated phenanthridines by oxidative alkoxycarbonylation–cyclization of 2-isocyanobiphenyls with carbazates

An iron-catalyzed synthesis of 6-carboxylated phenanthridines starting with readily prepared isocyanides and carbazates was developed. Reactions occurred via addition of alkoxycarbonyl radicals to the isocyanide group and subsequent intramolecular cyclization.     

Catalyst-free three-component approach to efficient synthesis of chromeno[4,3-b]pyrrol-4(1H)-one derivatives

A mild, efficient, and environmentally benign one-pot synthesis of functionalized chromeno[4,3-b]pyrrol-4(1H)-ones by a three-component domino reaction of 4-aminocoumarins, arylglyoxal monohydrates, and 1,3-dicarbonyl compounds in refluxing ethanol without the use of catalyst is reported. The present protocol features operational simplicity, short reaction time, good yields, and the absence of aqueous workup procedure and chromatographic separation.