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Synfacts 2014; 10(9): 0968
DOI: 10.1055/s-0034-1378969
Metal-Mediated Synthesis
© Georg Thieme Verlag Stuttgart · New York

Cyclotrimerization of Alkynes Mediated by n-BuLi–Ti(Oi-Pr)4

Contributor(s):
Paul Knochel
,
Diana Haas
Rassadin VA, Nicolas E, Six Y * École Polytechnique, Palaiseau, France
Ti(OiPr)4/nBuLi: An Attractive Reagent System for [2+2+2] Cyclotrimerisation Reactions.

Chem. Commun. 2014;
50: 7666-7669
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Further Information

Publication History

Publication Date:
18 August 2014 (online)

 
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Key words

titanium - lithium - cyclotrimerization

Significance

Six and co-workers report a cyclotrimerization for the construction of substituted benzenes and pyridines mediated by n-BuLi–Ti(Oi-Pr)4. The reaction allows for the selective formation of ABB heterotrimers from two different alkynes with similar electronic properties.


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Comment

This homotrimerization of arylacetylenes proceeds within minutes at room temperature with very good regioselectivity. However, when aliphatic alkynes are used, the homocyclotrimerization proceeds with much lower regioselectivity and affords 1,2,4- and 1,3,5-adducts in almost equimolar amounts.


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