2 Novel Strategies in the Post-glycosylation of Pre-formed Polymers . . . . . . . . . . . . . . . . . . . . . . 46
2.1 Copper-Catalyzed Azide–Alkyne Cycloaddition Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.2 Thiol Click Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.3 Amine Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3 Novel Applications of Glycopolymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.1 Therapeutic Application: Anticancer and Anti-HIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2 Biocompatible Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Glycopolymers are generally considered as synthetic macromolecules featuring sugar
moieties and have showed promise in some biorelated applications [1]. This field has
benefited from the development of elegant synthetic polymer chemistry, and the past
two decades have evidenced dramatic progress in the synthesis of functional
glycopolymers. Glycopolymer synthesis has been generally carried out by either
direct polymerization of glycomonomers or post-glycosylation of pre-formed
polymers [2]. As a special case, glycopolymers can also be synthesised via simultaneous copper-catalyzed azide-alkyne cycloaddition (CuAAC) and living radical
polymerization (LRP), which is a hybrid of the previous two strategies [3].
By the combination of living polymerization and click chemistry, different
strategies have been developed for the efficient synthesis of glycopolymers with
defined structure and function. These strategies have already been discussed in
detailed reviews separately by Haddleton, Stenzel, Cameron, Maynard and
co-authors [1, 2, 4–6]. The applications of glycopolymers such as therapeutic
drug delivery, multivalent recognitions with lectins and signal transduction have
been summarized in recent reviews by Cameron, Stenzel, Remzi, Kiessling and
co-authors [2, 7–9]. Thus, there has been very intensive research on glycopolymer
synthesis and application, and most of the research until 2011 has been summarized
in previous reviews. However, new strategies have been constantly emerging
during 2011–2013 and are described below.
1 Novel Strategies in the Direct Polymerization
of Glycomonomers
1.1 Ring-Opening Polymerization
Ring-opening polymerization includes cationic, anionic and enzymatic ring-opening
polymerization, which depend on whether the catalyst type or the reactive centre of
the propagating chain is a carbocation or carbanion. It has had a long history since
the 1950s and has been widely used for polymerization of different functional
cyclic monomers [10]. However, its application in the direct polymerization of
carbohydrate-containing cyclic monomers has been limited [11, 12]. Recently, the
Schubert group synthesized a glucose-substituted 2-oxazoline monomer (Fig. 1) via
40
Q. Zhang and D.M. Haddleton
2.1 Copper-Catalyzed Azide–Alkyne Cycloaddition Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.2 Thiol Click Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.3 Amine Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3 Novel Applications of Glycopolymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.1 Therapeutic Application: Anticancer and Anti-HIV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2 Biocompatible Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Glycopolymers are generally considered as synthetic macromolecules featuring sugar
moieties and have showed promise in some biorelated applications [1]. This field has
benefited from the development of elegant synthetic polymer chemistry, and the past
two decades have evidenced dramatic progress in the synthesis of functional
glycopolymers. Glycopolymer synthesis has been generally carried out by either
direct polymerization of glycomonomers or post-glycosylation of pre-formed
polymers [2]. As a special case, glycopolymers can also be synthesised via simultaneous copper-catalyzed azide-alkyne cycloaddition (CuAAC) and living radical
polymerization (LRP), which is a hybrid of the previous two strategies [3].
By the combination of living polymerization and click chemistry, different
strategies have been developed for the efficient synthesis of glycopolymers with
defined structure and function. These strategies have already been discussed in
detailed reviews separately by Haddleton, Stenzel, Cameron, Maynard and
co-authors [1, 2, 4–6]. The applications of glycopolymers such as therapeutic
drug delivery, multivalent recognitions with lectins and signal transduction have
been summarized in recent reviews by Cameron, Stenzel, Remzi, Kiessling and
co-authors [2, 7–9]. Thus, there has been very intensive research on glycopolymer
synthesis and application, and most of the research until 2011 has been summarized
in previous reviews. However, new strategies have been constantly emerging
during 2011–2013 and are described below.
1 Novel Strategies in the Direct Polymerization
of Glycomonomers
1.1 Ring-Opening Polymerization
Ring-opening polymerization includes cationic, anionic and enzymatic ring-opening
polymerization, which depend on whether the catalyst type or the reactive centre of
the propagating chain is a carbocation or carbanion. It has had a long history since
the 1950s and has been widely used for polymerization of different functional
cyclic monomers [10]. However, its application in the direct polymerization of
carbohydrate-containing cyclic monomers has been limited [11, 12]. Recently, the
Schubert group synthesized a glucose-substituted 2-oxazoline monomer (Fig. 1) via
40
Q. Zhang and D.M. Haddleton