A facile and convenient synthesis of acetic nitronic anhydrides from aliphatic nitroalkenes and lithium ketone enolates and the efficient conversion of these anhydrides to 1,4-diketones, alkylpyrroles, diketone monooximes, dihydro-1,2-oxazines, pyrrolidines, 2-hydroxypyrrolidines, and 1-pyrrolines are recorded.
In the presence of Pd(0) complexes, 2-ethoxy-2-propenyl diethyl phosphate was found to react with organotins to give the corresponding coupling products, showing to be a more efficient halo acetone equivalent compared with the corresponding acetate or carbonate. Reaction with tin enolates gave the 1,4-diketone in moderate to good yields.
1,4-diketones and 4-ketoaldehydes dimethylacetals can be prepared in good yields (65%–82%) by the cerium(IV) ammonium nitrate promoted reaction of ketones with isopropenyl acetate and vinyl acetate, respectively.
Palladium or ruthenium catalyzed cross-coupling of α-haloketones with tributyltin enolates gave unsymmetrical 1,4-diketones, The method was applied to the dihydrojasmone synthesis.
One-Pot Synthesis of 1,4-Diketones from Nitroalkenes and Ketones
作者:Masaaki Miyashita、Bahlul Z. E. Awen、Akira Yoshikoshi
DOI:10.1055/s-1990-26939
日期:——
A convenient one-pot synthesis of 1,4-diketones was achieved by the conjugate addition of lithium enolates of ketones to nitroalkenes, followed by in situ hydrolysis of the resulting lithium salts of aci-nitro compounds with aqueous hydrochloric acid in tetrahydrofuran.