The reaction of various secondary nitro compounds with 1.1 equivalents of potassium hydride in 1,4-dioxane and then with 0.10 equivalent of chlorotrimethylsilane gave the corresponding ketones in 62-90% yields. By a similar strategy, poly(1,3-diketones) were synthesized directly from nitroalkenes with sodium ethoxide, potassium hydride, and chlorotrimethylsilane in 1,4-dioxane. The use of chlorotrimethylsilane in a catalytic amount was the key to the success of this transformation; the use of an excess of chlorotrimethylsilane led to poor yields for the same reactions.Polymers with conjugated backbones show great potential in industry. 1 Some of these polymers are applied in photolithography, imaging technology, precise micro-fabrication, packing materials, etc. 2 Even more important are their valuable electronic and optical properties. 3 Among conjugated polymers of various types, polyketones show high thermostability, chemical resistance, and high fatigue strength. 4 Along the line of development of new methods in our laboratory 5-8 for the synthesis of functional polymers, 9,10 we planned to obtain polymers with a repeating 1,3-diketone unit 11-14 1 and 2, also known as polyketenes (Figure 1), by a new and efficient method. Figure 1Living polymerization strategy provides a smooth and controllable avenue for the conversion of nitroalkenes into polynitro materials. 15 On the other hand, the transformation of nitro materials to ketones is known as the Nef reaction, for which many conditions have been developed. 16 The first systematic application of the silicon g-effect to control an organic reaction was the siliconpromoted Nef reaction, 17 in which a silyl group is placed into the reaction substrate. Thus b-silyl ketones can be prepared from silicon-containing nitroalkenes using a one-flask method under mild conditions. Herein we report a different version of utilizing a silicon reagent to accomplish the Nef reaction. This new method would be suitable for the general synthesis of ketones and polyketones from the corresponding nitro compounds by the use of a silicon reagent in a catalytic amount.First, we polymerized b-nitrostyrene (3) by using sodium ethoxide as the initiator (Scheme 1). 15a,c The resultant multiple Michael adduct 5 was produced in 85% yield with molecular weight (MW) of 2.43 × 10 4 . In the second step, polymer 5 was treated with 1.1 equivalents of potassium hydride in 1,4-dioxane and then with 0.10 equivalent of chlorotrimethylsilane at 101°C for 24 hours. The corresponding poly(1-oxo-2-phenylethylene) (1) with molecular weight 1.94 × 10 4 was obtained in 78% yield. Furthermore, we prepared polymer 1 directly from b-nitrostyrene (3) by a newly developed one-flask method. bNitrostyrene (3) was treated with 0.050 equivalent of sodium ethoxide in 1,4-dioxane and then with 1.
