A total synthesis of (1R,5R)-3-phenylmethyl-4-thia-2,6-diazabicyclo [3.2.0]hept-2-en-7-one, a useful intermediate for the preparation of penem and cepham derivatives
The preparation of the thiazoline (1R,5R)-3-phenylmethyl-4-thia-2,6- diazabicyclo [3.2.0]hept-2-en-7-one (1) is presented. This compound, which has been extensively used as an intermediate for the synthesis of penems and cephams, has been obtained starting from a C-4 unsubstituted azetidinone by means of facile processes while chirality has been obtained through enzymatic resolution.
N,N-dibenzyloxycarbonylglycyl chloride as useful ketene equivalent in the synthesis of azetidin-2-ones
N,N-3-Dibenzyloxycarbonylaminoazetidin-2-ones have been conveniently prepared from N,N-dibenzyloxycarbonylglycyl chloride and imines or hexahydrotriazines. The β-lactams thus obtained could be monodeprotected by mild hydrogenolysis with Pd on carbon.