Alcoholysis of Methyl Aluminium Biphenoxides: Excellent Initiators for the Ring Opening Polymerisation of <i>ε</i>‐Caprolactone

Abstract

Abstract Several aluminium alkoxides are prepared, and their catalytic activities toward ring‐opening polymerisation of ε ‐caprolactone have been investigated. The reaction of [( μ ‐EDBP)AlMe] 2 (EDBP‐H 2 : 2,2′‐ethylidenebis(4,6‐di‐ tert ‐butylphenol)) with 2 molar equiv. of monomethylethylene glycol yields a five‐coordinated dimeric aluminium complex, ( 1 ). [( μ ‐EDBP)AlMe] 2 reacts with 2 molar equiv. of alcohol in toluene at ambient temperature to give a four‐coordinated dimeric aluminium complex, [(EDBP)Al( μ ‐OR)] 2 ( 2 : R = Me; 3 : R = Et; 4 : R = 4‐MeOC 6 H 4 ). However, the reaction of [( μ ‐EDBP)AlMe] 2 with 2 molar equiv. of benzhydrol in tetrahydrofuran (THF) gives a four‐coordinated monomeric complex, [(EDBP)Al(OCHPh 2 )(THF)] ( 5 ). Molecular structure of 1 as 20% ellipsoids, hydrogen atoms are omitted for clarity. magnified image Molecular structure of 1 as 20% ellipsoids, hydrogen atoms are omitted for clarity.