Chirality of poly(vinyl compounds), 13. Sterical requirements in analogues of trityl methacrylate for the preparation of optically active, single‐sense helical polymers

Abstract

s t y 1 methacrylate possesses two different substituents at the olefinic double bond. The larger one containing the trityl group forms the outside sphere of the helix in the corresponding polymers. In this paper the role of the second, smaller substituent is discussed. For this purpose four new monomers, methyl a-(trityloxymethy1)acrylate (3, ethyl a-(trityloxymethy1)acrylate (6), a-(trityloxymethyl)styrene (7). and trityl a-ethylacrylate (3), were prepared. Polymerizationexperiments showed that this substituent should be of minimum size to obtain a stable helix. More extended substituents though do not fit into the helical arrangement and therefore neither anionic nor radical polymerization was achieved.

Synthetic Helical Polymers: Conformation and Function

“…Helix-sense-selective polymerization has also been attempted for several bulky monomers including an acrylonitrile derivative and α-substituted acrylates. , Triphenylmethyl crotonate (TrC, 35 ) affords optically active, helical polymers by the polymerization using DDB−FlLi and PMP−FlLi complexes. , The polymers possess a nearly completely threo-diisotactic structure. Although the polymers indicate relatively small specific rotation ([α] D +5.6° and +7.4° for the samples with DP = 15 and 36, respectively), the optical activity is considered to be based on an excess helicity because the rotation was lost when the polymers were converted to the methyl esters.…”

Stereospecific Polymerization of Benzyl α-(Methoxymethyl)acrylate

“…However, the polymer was obtained in a few percent yield in toluene, 5 probably due to side reactions, 1,2-addition (carbonyl attack), and elimination of a phenoxide anion. Wulff et al also carried out the anionic polymerization of methyl R-((trityloxy)methyl)acrylate, 6 but no polymer was obtained, probably because of the bulky alkoxy group. Therefore, we designed BMMA as a monomer.…”

Asymmetric Polymerization

“…Helix -sense -selective polymerization of some other bulky monomers has been attempted using chiral initiators: Monomers 162b -d [222] and 163a [179b] did not give polymers probably due to the highly crowded monomer structures. On the other hand, bulky crotonate ( 163b ) afforded optically active, helical polymers by anionic polymerization in the presence of FlLi / DDB and FlLi / PMP [223,224] .…”