KEY WORDSPolyether / Ally! Side Chain / Three-Component Polycondensation / Dialdehyde / Trialkylsilane / Allylsilane / Trityl Perchlorate / There are two general approaches to the preparation of functional polymers. 1 In one approach the required functional group is attached to a readily available polymer by an appropriate reaction. The second approach is to synthesize an appropriate monomer with the desired functional group and then polymerize or copolymerize the monomer. The second approach is generally achieved by polymerization of vinyl monomers, and polycondensation has been rarely applied for this purpose except for some examples. 2 -4 In recent papers 5 we described a novel approach to synthesis of functional polymers by polycondensation, which simultaneously constructs both polymer backbone and functional side chains 6 such as the allyl groups and cyano groups from dialdehydes, diol disilyl ethers, and silyl nucleophiles (Scheme 1 ). This approach awoke our further interest in whether the diol disilyl ethers in the above polycondensation could be replaced with trialkylsilanes, because the silyl ether groups are formed in situ by the reaction of the formyl group with trialkylsilanes. 7 In addition, the amount of functional side chains could be arbitrarily controlled by changing the feed ratios of trialkylsilanes to the silyl nucleophiles, if the reactivity of trialkylsilanes toward the formyl group was not so different from that of the silyl nucleophiles. This paper reports the three-component polycondensation of dialdehyde (1), triethylsilane (2), and allyltrimethylsilane t To whom correspondence should be addressed.cat. TrCI04(trityl) perchlorate at various feed ratios, yielding polyethers with arbitrary amounts of the ally! side chains according to the feed ratios of 2 to 3 in one step (Scheme I).
EXPERIMENT AL
Model ReactionA round bottomed-flask equipped with a three-way stopcock was charged with trityl perchlorate (0.034 g, 0.1 mmol) and purged with argon. After the addition of dry CH 2 Cl 2 (I mL), the flask was cooled to -78°C, and a solution ofbenzaldehyde (0.212 g, 2.0 mmol) in CH 2 Cl 2 (1 mL) was added. After 5 min, a solution of 3 (0.137 g, 1.2 mmol) in CH 2 Cl 2 (0.5 mL) and solution of 2 (0.116 g, 1.0 mmol) in CH2 Cl 2 (0.5 mL) were successively added, and the mixture was stirred at -78°C for 2 h. The reaction mixture was quenched with aqueous NaHC0 3 and extracted with ether. The ether layer was washed with water and dried over MgS0 4 . After evaporation of the solvent, the crude product was purified with column chromatography on silica gel and a preparative HPLC to yield 4 7 b (31 % yield), 5 (23% yield), and 6 (27% yield). a-Allylbenzyl ether 5: IR (neat) 1641, 1082cm-1 ; 1 H NMR (CDC1 3 ) b 7.44-7.21 (m, !OH), 5. 89-5.69 (m, lH), 5.26-4.98 (m, 2H), 4.50-4.23 (m, 3H), 2.71-2.36 (m, 2H); 13 C NMR (CDCl 3 ) b 141. 9, 138.6, 134.9, 116.9, 81.3, 76.5, 42.7. a,a'-Diallylbenzyl ether 6: IR (neat) 1641, 1083 cm -1 ; 1 H NMR (CDC1 3 ) J7. !OH), 2H), 4H), 4.43 and 4.10 (2t, J=6.2Hz, 2H)...