SUBSTITUENT EFFECTS ON PHOTOADDITION OF DIPHENYLACETYLENE TO 1,4-NAPHTHOQUINONES

The photoaddition of diphenylacetylene to 1,4-naphthoquinone and the corresponding 2-methoxyl and acetoxyl derivatives was investigated. In all cases, cyclobutene formation occurred to varying extents depending on the 2 substituent, thereby establishing this process as a useful synthetic method. In addition, the work provides the first examples of simultaneous C4 and C3O cycloaddition of alkynes to quinones and, in the case of 1,4-naphthoquinone, a particularly attractive system for studying the effects of reaction variables on the competing modes of addition. © 1968, American Chemical Society. All rights reserved.