Synthesis and polymerization of 2,6,7-trioxabicyclo[2.2.2]octane and its derivatives

Abstract

Ten new 2,6,7-trioxabicyclo[2.2.2]octane derivatives, RC(OCH2)&R' [where R = H, R' = NOz R = H, R' = CH;OSO2C7H, (10); R CH3, R' = COOCH, (13); R = CH3, R' = COOC2H5 (14); R = CH,, R' = NO2 (15); and R = CH3, R' = NH2 (1611, were synthesized, and six other derivatives, 1-4, 11, and 12, were prepared by literature directions. Each of these bicyclic compounds was polymerized with boron trifluoride etherate as initiator at 0 "C. The polymers were usually obtained as highly crystalline white powders with high melting points accompanied by decomposition. These polymers were not soluble in any solvent without decomposition. Initiation with deliberately high initiator concentration gave soluble oligomers with T~~~ ca. 0.1 g/dL, indicating that most of the polymers had fairly high molecular weights. From IR and NMR spectroscopic results (of the oligomers) they possessed the structure (5); R = H, R' = NH2 (6); R = H, R' = N(CH3)Z (7); R = H, R' = NHCOCHS (8); R = H, R' = COOC2HS (9); IntroductionWith the objective of synthesizing linear stereoregular, high molecular weight analogues of polysaccharides, we have studied bicyclic orthoesters 2,6,7-trioxabicyclo-[2.2.l] heptane,' 2,7,8-trioxabicyclo[3.2.1]octane,2 and 2,8,9-trioxabicyclo[3.3.1]nonane.2 However, no stereoregular propagation has been observed. The molecular weight of these polymers has been low, and the polymers have all been liquid rubbers.The highly symmetrical 2,6,7-trioxabicyclo[2.2.2]octane system (1) has not been studied extensively before. Steuck3 showed that the 4-methyl derivative 2 underwent cationic polymerization. Bailey, Endo, and Saigo4 polymerized several derivatives of 1 with boron trifluoride at elevated temperatures to open both rings, causing volume expansion. In the present paper, we describe the synthesis and polymerization of 2,6,7-trioxabicyclo[2.2.2]octane (1) and its derivatives 2-16.

Synthesis and Polymerizability of Atom-Bridged Bicyclic Monomers

“…They are synthesized from condensation of triols with ethyl orthoformate, again removing the bicyclic monomer as it forms [61][62][63][64][65][66]. This topic has been reviewed [42][43][44]67].…”

“…This topic has been reviewed [42][43][44]67]. [64] O O O 56 [65,66] O O 57 [65] O For the bicyclic acetals and orthoesters, oxonium ion propagation is still predominant. However, for these monomers, cleavage of the oxonium ion to oxacarbenium ion can lead to loss of stereoregularity [67].…”

First observation of the cationic equilibrium polymerization of a bicyclo ortho ester

“…After the mixture was stirred for 24 h, it was quenched by the addition of triethylamine (3 drops). EtBOE was isolated by preparative HPLC (Japan Analytical Industry LC-908 system, equipped with two polystyrene gel columns (JAI gels H1, H2) using CHCl 3 as an eluent at a flow rate of 3.8 mL/min) from the mixture: yield 62 mg (43%); 1 H-NMR (400 MHz, CDCl 3 ) ␦ 5.5 (s, 1H), 3.9 (s, 6H), 1.3 (q, J ϭ 8.14 Hz, 2H), 0.8 (t, …”

“…Hall et al have reported that bicyclo ortho esters (BOEs) undergo single ring-opening polymerization at low temperature 3 and double ring-opening polymerization at high temperature. However, the detailed polymerization behavior of BOEs is not clear yet, much less the equilibrium character of the polymerization.…”

Ring-opening isomerization addition reaction of bicyclo ortho esters with acid chlorides. Model reaction for development of a novel polyaddition reaction accompanying ring-opening isomerization

“…High molecular weight polymers are favorable for practical use from the view point of physical property. In general, it is difficult to obtain high molecular weight polymers from BOEs due to main chain fission during the polymerization [5][6][7] . This problem may be overcome by copolymerization of BOEs with other monomers.…”