ABSTRACT
Herein, we report a highly diastereoselective construction of fused carbocycles using four successive pericyclic reactions.
Subject(s)
Alkynes/chemistry , Ethers/chemistry , Polycyclic Compounds/chemical synthesis , Alkynes/radiation effects , Ethers/radiation effects , Microwaves , StereoisomerismABSTRACT
In this article, we report a highly diastereoselective new method for the generation of quaternary carbon centers through an anionic oxy-Cope/alkylation sequence where the diastereoselectivity is induced by the conformation of a macrocyclic tetrasubstituted enolate. The use of our methodology culminated in the formal total synthesis of (-)-mesembrine (34) in 11 steps from known starting materials.
Subject(s)
Carbon/chemistry , Indole Alkaloids/chemical synthesis , Macrocyclic Compounds/chemistry , Alkylation , Magnetic Resonance Spectroscopy , Models, Chemical , Molecular Conformation , StereoisomerismABSTRACT
[reaction: see text] Herein, we present a successful synthesis of the tricyclic core of vinigrol (1). Our approach takes advantage of a highly regioselective intramolecular Diels-Alder reaction of the diene 11 to construct two rings of the tricyclic vinigrol skeleton 12.
Subject(s)
Diterpenes/chemical synthesis , Macrocyclic Compounds/chemical synthesis , Diterpenes/chemistry , Macrocyclic Compounds/chemistry , Molecular StructureABSTRACT
Under conventional heat (135-145 degrees C) or microwave irradiation and 1 equiv of acetic anhydride, ortho-substituted aryl-oximes undergo a novel sp3 C-H activated cyclization to produce the corresponding isoindoles, and aliphatic oximes afford the corresponding dihydropyrroles. The cyclization occurs with various substrates in good yield (46-82%) leading to unique spiro-fused and cyclic imines. An initial mechanistic investigation suggests the reaction occurs via a nitrenium or vinyl nitrene intermediate. [reaction: see text]
Subject(s)
Combinatorial Chemistry Techniques , Imines/chemical synthesis , Oximes/chemistry , Spiro Compounds/chemical synthesis , Acetic Anhydrides/chemistry , Cyclization , Hot Temperature , Imines/chemistry , Indoles/chemistry , Microwaves , Models, Chemical , Pyrroles/chemistry , Vinyl Compounds/chemistryABSTRACT
We report a gold-catalyzed benzannulation of 3-hydroxy-1,5-enynes to generate tetrahydronaphthalenes. This mild process proves to be an effective method to synthesize various metasubstituted aromatic rings in good yields. [reaction: see text]