The total synthesis of crystalline dl-prostaglandin E1 and its methyl ester via bicyclo[3.1.0]hexanone intermediates is described. The same reaction sequence also produces dl-8-isoprostaglandin E1, the 15-epimers of these prostaglandins, and also dl-PGA1 and dl-PGB1 methyl esters. © 1969, American Chemical Society. All rights reserved.