A new stereocontrolled approach to fused polycyclic compounds containing a diketopiperazine ring

Article abstract of DOI:10.1016/j.tetasy.2005.08.034

Representative (1S)- and (4S)-alkyl-1,4-dihydropyrazino[2,1-b]quinazoline- 3,6-dione lactim ethers were regio- and diastereoselectively alkylated after metallation to give the corresponding 1,4-trans-isomers with retention of the stereocentres. The result