Tetrahedron letters

Syntheses of [5]-helicene by McMurry or carbenoid couplings

F Dubois, M Gingras

Index: Dubois, Fabien; Gingras, Marc Tetrahedron Letters, 1998 , vol. 39, # 28 p. 5039 - 5040

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Citation Number: 59

Abstract

Short syntheses of [5]-helicene have been accomplished under thermal conditions, without using photochemistry and high dilution. Key reactions comprised a McMurry coupling of a dialdehyde or a carbenoid-type coupling of aromatic bis (bromomethyl) moieties. The last coupling provided a 7290 yield of [5]-helicene on a gram-scale (15 min., 0° C).