The diastereoselective Michael addition of an enantiopure phosphite to nitroalkenes
and α,β-unsaturated malonates is described. High asymmetric inductions were obtained
using a readily available TADDOL auxiliary. Racemization-free cleavage of the auxiliary
led to α-substituted β-nitro phosphonates and β-substituted β-phosphono malonates
in good yields and high enantiomeric excesses, respectively. An extension of the method
to the synthesis of α,β-disubstituted β-nitrophosphonates with two new neighboring
stereogenic centers is also reported.
Michael addition - nitroalkenes - phosphonates - P-C bond formation - asymmetric synthesis
