Radical ring-opening 4-methylene-1,3-dioxolane

TABLE 1. Copoly merization Scoping Reactions Using the Radical Ring-Opening Polymerization Monomer, 5-Methylene-2-phenyl-l,3-dioxolan-4-one, with Methyl Methacrylate... 

The preparation of the radical ring-opening polymerization monomer, 5-methylene-2-phenyl-l,3-dioxolan-4-one, (I), is illustrated in Eq. (1). 

The radical ring-opening elimination polymerization of 4-methylene-l,3-dioxolane stimulated us to construct a novel template polymerization (3). The concept is that polymers bear polymers. Polymer-supported monomer, which had a structure of 2,2-dipheny 1-4-methylene-1,3-dioxolane, reacted with radical species to afford polyketone and copolymer of styrene with vinylbenzophenone as newborn polymer and template, respectively (Figure 12). These polymers were easily separated by fractional precipitation without any particular chemical treatment after polymerization. On the other hand, common template polymerization requires annoying procedures for the separation of obtained polymers form template. On this point, our novel template polymerization system differs from conventional template polymerization. 

Pan, C.Y. and Lou, X.D. (2000) Living free radical ring-opening polymerization of 2-methylene-4-phenyl-l,3-dioxolane by atom transfer radical polymerization. Macromol. Chem. Phys., 201, 1115. 

The electron transfer reaction of gem-diarylmethylenecyclopropanes (60) with singlet sensitizers results in the exchange of the exo-methylene and the secondary cyclopropane carbons [241], The chloranil photo-sensitized reaction generates two unusual cycloaddition products (61, 62) [242], whereas the tetracyanoethylene sensitized oxygenation produces the respective dioxolanes [238]. These reactions are compatible with a ring-opened radical cation, and CIDNP experiments have... 

Methylene- 1,3-dioxolane (15) is polymerized by peroxide initiator to produce a polyester 16 which is regarded as the product of the hypothetical ring-opening polymerization of the non-polymerizable heterocycle of y-butyrolactone (Eq. (14)).13). The opening of the cyclic species bearing a free radical 17 is the key step. 

Sugiyama and co-workers (69,70) report a very interesting template process by the ring-opening polymerization induced by radicals. The polyethylene template was connected with 2,2-diphenyl-4-methylene-l,3-dioxolane groups by the covalent bonds. The process can be illustrated by the following reaction ... 

R)- and (S)-f-Butyl-5-methylene-l,3-dioxolan-4-one, a Chiral a-Alkoxy Acrylate. It is also possible to introduce an ex-ocyclic double bond onto the dioxolanone ring, as in compounds (9)-(ll), derived from lactic and malic - acids. These a,3-unsaturated carbonyl derivatives are acceptors for radical additions and undergo cycloadditions with dienes and heterodienes. The Diels-Alder adduct (12) of ent-(9) with cyclopentadiene is formed with exo selectivity (96 4) and serves as aprecursor to norbomenone (13). Cycloadduct (14), obtained from methylenedioxolanone (9) and an open-chain triene, is also the result of an exo addition and is used in tetronolide synthesis. ... 

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