Department of Chemistry, The Pennsylvania State University, York Campus, York, Pennsylvania 17403 and Section on Medicinal Chemistry, Laboratory of Chemistry, National Institute of Arthritis, Metabolism and Digestiue Diseases, National Znstitutes of Health, Rethesda, Maryland 20014 Received November 9, 1978 ... Synthesis of five 4,5,6,7-tetrasubstituted-3a,4,7,7a-tetrahydro -4,~-methano-l,3-benzodioxole-2,~-diones ... A number of' years ago we became ...