Asymmetric Polymerization of Carboxylic Acid Derivatives

A lipase-catalyzed asymmetric polycondensation have been achiewd uang tte racemic diester 6 and tte achiral did 7 (or tte achiral diester mid tte racemic diol) in an organic sdvait [3. Optically active tiimers and pentamers 8 were 

Synthesis of an optically active xy-sutetituted polyester 15 by lipase-catafyzed polymerization has been demonstrated [38]. A highly enantioselective polymerization of a chiral, epoxide-substituted diester 13 with 1,4-butanediol 14 was performed iBing Porcine pancreatic lipase (PPL) as catalyst. The molar 

Another advantageous feature of enzymes in an esterification reaction lies in their ability to distinguish a specific hydroxyl group of a complex polyalcohol like sugar derivatives. KUbanov et aL found that Bacillus subtilis protease (subtilirin) catalyzes the regioselective acylation disaccharides 16, as well as nucleosides and related compounds in N,N-dimethylformamide [40]. 

Sucrose-containing linear polyesters 19 have been prepared using various enzymes from sucrose 17 and d rboxylic acid diesters 18 [41]. The polycondensation reaction proems in anhydrous pyridine. An alkaliiK protease from a Bacillus sp. catalyzes the esterification of sucrose with bis(2,2,2-trifluoro-ethyladipate) to give a sucrose-containing polyester with M = 2100. The sucrose polyester is highly water soluble and soluUe in polar organic solvents. 

The polyester is degraded by the same enzyme in an aqueous solution (pH 7) to an of c.a. 900 after 9 days. This polymer may have applications as a water-absorbent, biodegr laUe plastic. 

A lipase-catalyzed asynuiKstric polycondensation have been achieved using the racemic diester 6 and the achiral diol 7 (or the achiral diester and the racemic diol) in an organic solvent [3. Optically active trimers and pentamers 8 were 

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