10.1021/acsmacrolett.7b00775.s001
Xin Wang
Xin
Wang
Yaya Liu
Yaya
Liu
Zhenjiang Li
Zhenjiang
Li
Haixin Wang
Haixin
Wang
Hailemariam Gebru
Hailemariam
Gebru
Siming Chen
Siming
Chen
Hui Zhu
Hui
Zhu
Fulan Wei
Fulan
Wei
Kai Guo
Kai
Guo
Organocatalyzed Anionic Ring-Opening Polymerizations
of <i>N</i>‑Sulfonyl Aziridines with Organic Superbases
American Chemical Society
2017
MTBD
loading
propagating polymer chains
mol
tosylaziridine
DBU
TiPP
TMG
SEC
Bu-P 4
BnN
catalyst
superbase
PrNCH 2 CH 2
AROP
2- methyl
metal-free
Organocatalyzed Anionic Ring-Opening Polymerizations
initiator
aziridine
2017-11-14 18:52:08
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Organocatalyzed_Anionic_Ring-Opening_Polymerizations_of_i_N_i_Sulfonyl_Aziridines_with_Organic_Superbases/5601364
The
anionic ring-opening polymerizations (AROPs) of <i>N</i>-sulfonyl aziridines, in the presence of organic superbases including
phosphazene (<i>t</i>-Bu-P<sub>4</sub>), Verkade’s
base (P(<i>i</i>-PrNCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N, TiPP), DBU, MTBD, and <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-tetramethylguanidine
(TMG), using <i>N</i>-benzyl-<i>p</i>-toluenesulfonamide
(BnN(H)Ts) as initiator were explored to produce metal-free poly(sulfonylaziridine)s.
Among the superbases used, the catalytic activity was found directly
proportional to their basicity. Remarkably, <i>t</i>-Bu-P<sub>4</sub> and TiPP gave a living/controlled AROP of 2-methyl-<i>N</i>-tosylaziridine (TsMAz), where <i>t</i>-Bu-P<sub>4</sub> performed better, affording the metal-free and well-defined
poly(sulfonylaziridine)s with high molar masses (<i>M</i><sub>n</sub>(SEC) > 30 kg mol<sup>–1</sup>) and low dispersities
(<i><i>Đ</i></i> < 1.10) in 3.5 h. For
the less reactive monomers of 2-methyl-<i>N</i>-ethylsulfonyl
aziridine (EsMAz) and 2-phenyl-<i>N</i>-tosylaziridine (TsPhAz), <i>t</i>-Bu-P<sub>4</sub> showed the same excellent catalytic efficiency
(30 equiv, conv. > 95%, 5 h). The organocatalyzed AROP allowed
the
use of lower catalyst (<i>t</i>-Bu-P<sub>4</sub>) loading
than the amount of initiator (BnN(H)Ts), but the propagating polymer
chains were as many as the number of equivalents of the introduced
initiators, which could lower the loading of catalyst used to amounts
as low as 0.05 mol %.