Cyclo-oligomerization and rearrangement of some phenylated diynes by the RhCl 3Aliquat 336 and by the H 2PtCl 6Aliquat 336 catalysts under phase transfer conditions

Abstract

The phenylated diynes 3,3′-oxybis(1-phenyl-1-propyne) ( 3), its thio-analog 4, 1,2-bis(phenylethynyl)benzene ( 5) and 1,8-bis(phenylethynyl)naphthalene ( 6) were reacted, under phase transfer conditions, in the presence of the ion pairs generated from Aliquat® 336 and either aqueous RhCl 3 or H 2PtCl 6. The nature of the products proved to depend on the catalyst employed. The rhodium catalyst promotes the conversion of 3 into a mixture of trimer 8 and dimer 7a, as well as the hydrolysis of the latter compound to give 1,3-dihydro-4,6,7-triphenyl-5-isobenzofuranmethanol ( 9). The sulfur compound 4 yields only hydrolysis-resistant 1,3-dihydro-5-[2-propynyl(thiomethyl)]benzo[ c]thiophen ( 7b), and 6 forms mainly dimer 17 accompanied by small amounts of 7-phenyl- and 7-chloro-12-phenylbenzo[ k]fluoranthene ( 16a and 16b, respectively). The platinum catalyst promotes particularly intramolecular cycloaddition reaction of the diynes. Compound 3 is transformed almost entirely to 1,3-dihydro-9-phenylindeno[1,2- c]pyran ( 12), 5 is isomerized to give solely 5-phenylindeno[1,2- a]indene ( 15), and 6 yields 16a and 12-phenylindino[2,1- a]phenalene ( 18), as the minor and major products.