Total Synthesis and Evaluation of (.+-.)-N-(tert.-Butyloxycarbonyl)-CBI, (.+-.)-CBI-CDPI1, and (.+-.)-CBI-CDPI2: CC-1065 Functional Agents Incorporating the Equivalent 1,2,9,9a-Tetrahydrocycloprop(1,2-c)benz(1,2-e)indol-4-one (CBI) Le