Synthesis of Novel-dl-α-Tocopherol-Based and Sterically-Hindered-Phenol-Based Monomers and Their Utilization in Copolymerizations over Metallocene/MAO Catalyst Systems. A Strategy To Remove Concerns about Additive Compatibility and Migration

In this paper we present an initial study on various synthetic routes to novel polymerizable dl-α-tocopherol derivatives and to a styrenic sterically hindered phenol which was stimulated by our desire to conduct copolymerization with these monomers with α-olefins over different metallocene/methylalumoxane (MAO) catalyst systems. The syntheses of 6-hydroxyl-2,5,7,8-tetramethyl-2-(but-3-enyl)chroman (1) and 5,7,8-trimethyl-3-(hex-5-enyl)benzofuran-6-ol (2) were achieved by cyclocondensation of trimethylhydroquinone (TMHQ) with 3-methylhept-1,6-dien-3-ol and 2,7-octadienol, respectively. However, the latter tocopherol compound (2) could only be obtained in low yields, and all our attempts to isolate the product from its ring-opened isomers failed. This can be attributed to the fact that the reaction between TMHQ and 2,7-octadienol gave rise to a highly complex reaction mixture. Compound 3, 6-hydroxyl-2,2,8,9-tetramethyl-6-allylchroman, was prepared from the corresponding allylchromanoxy ether via Claisen rea...