Nitroalkenes, reactions with phosphites

The base-catalyzed reaction of dialkyl phosphite with nitroalkenes results in the formation of alkenyl phosphonates (Eq. 4.33).39... 

Noltes et al. [31] have already described the reaction of diethylzinc with diphe-nylphosphane leading to organozinc-phosphorus adducts which have been shown to be very reactive but very insoluble. In our synthesis of the phosphite 45 with the nitroalkenes 46 in the presence of Et2Zn the precipitation of a solid could be observed as well, which was unreactive at -78 °C but underwent addition to the nitroalkenes at 0 °C. In the presence of TMEDA even at these low temperatures the desired Michael adducts 47 were formed with very good yields and high diastereomeric excesses (de - 84-96%) (Scheme 1.1.12). After removal of the... 

A parallel series of reactions has been observed for tris(2-chloroethyl)phosphite . The formation of diethyl (2-oxoalkyl)phosphonates by the oxidation (by m-chloroperoxyben-zoic acid) of the products from the interaction of triethyl phosphite and nitroalkenes in the presence of TiCl4, is consistent with the intermediate formation of C-phosphorylated aci-nitro complexes When the phosphite triester species is a dialkyl trimethylsilyl phosphite. 

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