Rapid alcoholysis of cyclic esters using metal alkoxides: access to linear lactyllactate-grafted polyglycidol

• Published in: New journal of chemistry Vol. 47; no. 6; pp. 271 - 275
• Main Authors: Yimthachote, Supajittra, Phomphrai, Khamphee
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.02.2023
• Subjects: Alcohols; Alkoxides; Biodegradability; Esters; Lactones; Monomers; Titanium; Zirconium
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d2nj05564c

A facile alcoholysis of l -lactide (LA) and lactones was developed using inexpensive and commercially available Al(O i Pr) 3 ( 1 ), Ti(O i Pr) 4 ( 2 ), and Zr(O i Pr) 4 . i PrOH ( 3 ) yielding alkyl ( S , S )-lactyllactates and hydroxy esters. Complex 1 was the most efficient for the methanolysis of LA at 70 °C finishing very rapidly within 10 min selectively giving 99% methyl ( S , S )-lactyllactate. The alcoholysis can be extended efficiently to other functional alcohols containing triple bonds, and methacrylate, and epoxide groups. The alcoholysis of LA by 1 with glycidol gave glycidyl ( S , S )-lactyllactate as a new epoxide monomer in excellent yield. This monomer can be polymerized selectively at the epoxide group by 1 giving a novel linear polyglycidol having precisely one biodegradable lactyllactate unit grafted on each glycidol molecule that has not been accessible by previous methods. A convenient catalytic alcoholysis was developed to decorate precisely one unit of lactyllactate per repeating unit onto a linear polyglycidol backbone.