Living Ring-Opening Polymerization of <i>N</i>-Sulfonylaziridines:  Synthesis of High Molecular Weight Linear Polyamines

Stewart, Ian; Lee, Cameron C.; Bergman, Robert G.; Toste, F. Dean

doi:10.1021/ja0554357

Cited by 114 publications

(140 citation statements)

References 10 publications

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“…To this end, we were inspired by observations made during the course of our investigation of gold-catalyzed alkene cyclopropanation using propargyl esters as carbene precursors. 14 During these studies we noted that the cis - trans diastereomeric ratio of the cyclopropanation product depended on the steric properties of the phosphine ligand on gold. The observed selectivity for the cis isomer was rationalized by a concerted cyclopropanation model, involving the intermediacy of a cationic gold(I)-carbene intermediate, whose bonding and reactivity have subsequently been investigated by our research group and others (Scheme 2).…”

Section: Enantioselective Reactions Catalyzed By Bis(phosphine)digoldmentioning

confidence: 99%

Development of Catalysts and Ligands for Enantioselective Gold Catalysis

2013

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CONSPECTUS The use of Au(I) complexes for the catalytic activation of C-C π-bonds has been the subject of intense investigation in the last decade or so. The facile formation of carbon-carbon and carbon-heteroatom bonds facilitated by gold naturally led to efforts to render these transformations enantioselective. Early examples of enantioselective gold-catalyzed transformations have focused on bis(phosphinegold) complexes derived from axially chiral scaffolds. Although these complexes were highly successful in some reactions like cyclopropanation, careful choice of the weakly coordinating ligand (or counterion) was needed to obtain high levels of enantioselectivity for the case of allene hydroamination. These counterion effects led us to use the anion itself as a source of chirality, which was successful in the case of allene hydroalkoxylation. In order to expand the scope of reactions amenable to enantioselective gold catalysis to cycloadditions and other carbocyclization processes, a new class of mononuclear phosphite and phosphoramidite ligands was developed to supplement the previously widely utilized phosphines. Finally carbene ligands, in particular, the acyclic diaminocarbenes, have also been successfully applied to enantioselective transformations.

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Section: Enantioselective Reactions Catalyzed By Bis(phosphine)digoldmentioning

confidence: 99%

Development of Catalysts and Ligands for Enantioselective Gold Catalysis

2013

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“…Replacement by an electron‐withdrawing group facilitates this, while simultaneously activating the ring. In one single work it has been reported that tosylation or mesylation of aziridines enables anionic ring‐opening polymerization …”

Section: Introductionmentioning

confidence: 99%

Aziridine Termination of Living Anionic Polymerization

Thomi

Wurm

2014

Macromol. Rapid Commun.

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A switch from carbanions to aza-anions is performed by the addition of N-tosylaziridine (TAz) to living poly(styryl) (PS) chains. This is the first example of carbanionic aziridine ring-opening which was previously activated by amidation with a tosyl group to enable nucleophilic ring-opening by the living chain end. Poly(styrene)-tosylaziridines (PS-TAz) with narrow molecular weight distributions and variable molecular weights are synthesized. The removal of the tosyl group and subsequent functionalization is shown, evidencing quantitative transfer to azaanionic species. All polymers are characterized in detail by (1) H NMR spectroscopy, DOSY (1) H NMR spectroscopy, and size exclusion chromatography (SEC). This strategy allows the introduction of amine groups via anionic polymerization in analogy to the well-established epoxide termination.

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“…Deuterated solvents were purchased from Deutero GmbH. N ‐benzyl methanesulfonamide (BnNHMs), 2‐methyl‐ N ‐tosylaziridine (TsMAz), and 2‐methyl‐ N ‐mesylaziridine (MsMAz) were synthesized according to already published procedures and dried by azeotropic distillation from benzene to remove traces of water . 2‐Methylaziridine was distilled from CaH 2 prior use.…”

Section: Methodsmentioning

confidence: 99%

4‐Styrenesulfonyl‐(2‐methyl)aziridine: The First Bivalent Aziridine‐Monomer for Anionic and Radical Polymerization

Gleede

Rieger

Homann-Müller

et al. 2017

Macro Chemistry & Physics

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4‐Styrenesulfonyl‐(2‐methyl)aziridine (StMAz), the first orthogonal aziridine monomer, for both anionic ring‐opening and radical polymerization is presented. Both polymerization pathways are accessible without using protective groups. Aza‐anionic ring‐opening polymerization (A‐AROP) of StMAz and other methyl‐aziridine derivatives provide multifunctional polyaziridines. Molecular weights between 3000 and 13 000 g mol−1 are obtained with low molecular weight dispersities (Ð = 1.1). The amount of vinyl groups in linear polyaziridines from A‐AROP depends on the monomer/comonomer ratio. The vinyl groups of P(StMAz)‐ homo‐ or copolymers are entirely convertible by thiol‐ene addition. This allows modification with multiple functional groups. Free radical polymerization of StMAz leads to polyalkylenes with aziridine side groups, which are known to be efficiently addressable via nucleophiles. Polysulfonamides still belong to a rather new class of polymers accessible by anionic polymerization. Enlarging the scope of postpolymerization modifications on polyaziridines/‐sulfonamides is important for further macromolecular architectures. The aziridine and the vinyl group are combined to develop the first orthogonal monomer for aza‐anionic polymerization and radical polymerization.

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Living Ring-Opening Polymerization of N-Sulfonylaziridines: Synthesis of High Molecular Weight Linear Polyamines

Cited by 114 publications

References 10 publications

Development of Catalysts and Ligands for Enantioselective Gold Catalysis

Development of Catalysts and Ligands for Enantioselective Gold Catalysis

Aziridine Termination of Living Anionic Polymerization

4‐Styrenesulfonyl‐(2‐methyl)aziridine: The First Bivalent Aziridine‐Monomer for Anionic and Radical Polymerization

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