217076-66-9

Upstream product

• 217076-67-0 (E,Z)-1-phenyl-2,5-dimethyl-1,4-pentadien-3-one 
• 673-32-5 1-Phenylprop-1-yne 
• 109480-79-7 (E)-N-methoxy-N-methyl-2-butenamide 
• 101-39-3 2-methyl-3-phenyl-2-propenal 

Downstream Products

• 128192-10-9 2,4-dimethyl-3-phenyl-2-cyclopenten-1-one 

Relevant academic research and scientific papers

Regioselective synthesis of enones via a titanium-promoted coupling of unsymmetrical alkynes with Weinreb amides

A modular titanium-promoted coupling of unsymmetrical internal alkynes with Weinreb amides is described. The coupling reaction takes place at room temperature and affords E-trisubstituted enones in moderate to good yields with high levels of regioselectivity. The system shows moderate chemoselectivity.

Ionic hydrogenation of oxyallyl intermediates: The reductive nazarov cyclization

Cyclization of tri- and tetrasubstituted dienones 1 under Lewis acidic conditions in the presence of triethylsilane led to formation of either silyl enol ethers 6 or cyclopentanones 7 in good to excellent yields, depending on work-up conditions. The proposed mechanism involves initial Nazarov cyclization to give oxyallyl intermediates 5, which are intercepted via intermolecular transfer of hydride. The reactions proceeded cleanly with as little as 2 equiv. of silane and in most cases catalytic amounts of Lewis acid could be used. Trapping with Et3SiD occurs at the less substituted terminus in unsymmetrical cases. (C) 2000 Elsevier Science Ltd.

The reductive Nazarov cyclization

Tri- and tetrasubstituted 1,4-dien-3-ones 1 were treated with Lewis acid in the presence of triethylsilane, furnishing either silyl enol ethers 4 or cyclopentanones 5 in good yields, depending upon work-up conditions. This reaction is presumed to occur th