title: [Total synthesis of marine cyclic guanidine compounds and development of novel guanidine type asymmetric organocatalysts].
abstract: Crambescidins and batzelladines, novel marine guanidine alkaloids, have unique pentacyclic and tricyclic guanidine core structures, respectively. They display a considerable array of biological activity and not surprisingly have attracted considerable synthetic interest. The first total synthesis of crambescidin 359 (7) and stereoselective total synthesis of batzelladine D (11) were accomplished based on a successive 1,3-dipolar cycloaddition reaction strategy. During synthetic studies of 7, the absolute stereochemistry was revealed. Based on the structure of 7, the novel C2-symmetric pentacyclic guanidine compounds 69a-d were designed and synthesized as guanidine organocatalysts. The catalyst 69b works efficiently as an asymmetric catalyst of the alkylation reaction of the glycynate-benzophenone Schiff base 73, which gives 74 with 80-90% ee.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. nagasawa@iam.u-tokyo.ac.jp
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagasawa
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis*; D000818:Animals; D002384:Catalysis; D015195:Drug Design; D006146:Guanidines / Q000138:chemical synthesis*; D011743:Pyrimidines / Q000138:chemical synthesis; D013141:Spiro Compounds / Q000138:chemical synthesis; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids; D006146:Guanidines; D011743:Pyrimidines; D013141:Spiro Compounds; C410707:batzelladine D; C449038:crambescidin 359