Hydrophosphonylation of chiral hexahydroquinoxalin-2(1H)-one derivatives as an effective route to new bicyclic compounds: Aminophosphonates, enamines and imines

Abstract A series of new aminophosphonate and phosphonic acid derivatives of hexahydroquinoxalin-2(1 H )-ones and tetrahydroquinoxalin-2(1 H )-ones were synthesised via hydrophosphonylation of the corresponding bicyclic imines with various dialkyl or diaryl H -phosphonates, H -phosphinates or H -phosphine oxides as phosphorus nucleophiles. The utility of the obtained compounds was demonstrated by their application as a source of phosphonate carbanion in the Horner-Wadsworth-Emmons (HWE) reaction leading to new bicyclic amines with an exocyclic, and unexpectedly, also endocyclic double bond depending on the structure of the aldehyde used.