Cycloaddition von phenylarsinen an pentadiin-1,4-one-3 und 3-methylenpentadiine-1,4: Elektrocyclische reaktionen von 2,3-bis-methylen-arsolenen-4

The radicalic cycloaddition of phenylarsine and trimethylsilylsubstituted phenylarsines to pentadiyn-1,4-ones-3 yields the 2-methylene-arsolene-4-ones-3; these ketones react with diphenylketene to give the substituted 2,3-bis-methylene-arsolenes-4, which undergo thermal electrocyclic reactions. The resulting benzannelated arsolenes are dehydrogenated to the corresponding arsoles, which can be isolated by reaction of phenylarsine with 3-diphenylmethylene-pentadiynes-1,4-directly.