Studies On Annulation Reaction Of ?,?-Unsaturated Carbonyl Compounds Containing Amino Groups

In organic synthesis, ?,?-unsaturated carbonyl compounds are the significant important precursors, which have attracted numerous the scientists'attentions, because of the advantage of readily available and the diversity of construction. In this area, the annulation reactions of ?,?-unsaturated carbonyl compounds have been widely reported. However, annulation reactions of a,p-unsaturated carbonyl compounds containing amino groups have been studied less so far. In this thesis we mainly develop ?,?-unsaturated carbonyl compounds of nitrogen-containing reacting with various nucleophiles or dipoles such as dimethyl glutaconate, active methylene compounds and diazocarbonyls.(1) We have developed a new strategy for the efficient synthesis of polysubstituted isoquinolone and phenanthridinone derivatives from ?,?-unsaturated carbonyl compounds with dimethyl glutaconate, involving a tandem Michael addition/intramolecularaldol/intra molecular aza-annulation/aromatization procedure in a single step, in high to excellent yields by using mild transitionmetal-free conditions and readily available acyclic substrates.(2) A base-mediated aerobic oxidation of the C-H bond adjacent to the N-atom of a secondary amine to form an imine intermediate under mild metal-free basic conditions has been developed. Accordingly, this new strategy has been successfully applied to the synthesis of various di-, tri-, and tetra-substituted a-amino cyclopentenones. This tandem aerobic oxidative [4+1] carbocyclization reaction can proceed under very mild metal-free conditions using O2 as the oxidant in a single operation to give the corresponding products in good to excellent yields. Furthermore, it is the first reported to sp3-sp3 carbon-carbon bonds coupling only using O2 from the air without any metals or addition oxidants.(3) It is the first time that a-diazocarbonyls have been used as highly active N-terminal electrophiles in the presence of DBU (1,8-diazabicyclo-[5.4.0] undec-7-ene) as catalysts. The C-N bond-forming reactions of active methylene compounds as C nucleophiles with a-diazocarbonyls as N-terminal electrophiles proceed quickly under ambient conditions, because of the formation of the reactive N-terminal electrophilic intermediates by DBU catalyzed, producing hydrazone, hydrazono and pyrazole. The new reactions which could tolerate numberous a-diazocarbonyls and active methylene compounds not only create a simple and efficient way to form C-N bond, but also a-diazocarbonyls as N-terminal electrophiles have laid the foundation for the further applications in organic synthesis.