title: Tandem Rh(i)-catalyzed [(5+2)+1] cycloaddition/aldol reaction for the construction of linear triquinane skeleton: total syntheses of (+/-)-hirsutene and (+/-)-1-desoxyhypnophilin.
abstract: A tandem reaction involving a Rh(I)-catalyzed two-component [(5+2)+1] cycloaddition and an aldol condensation has been developed to construct the tricyclo[6.3.0.02,6]undecane skeleton and its heteroatom-imbedded analogues. Meanwhile, this method has been successfully applied to natural product synthesis for the first time. The present strategy enables a straightforward approach to the natural linear triquinane skeleton, as demonstrated by concise and step economical syntheses of hirsutene and 1-desoxy-hypnophilin, whereby the linear triquinane core is diastereoselectively established in one manipulation with correct placement of all stereocenters, including two quarternary centers. This first application of the Rh(I)-catalyzed [(5+2)+1] cycloaddition in natural product synthesis highlights the efficiency of this methodology for constructing complex fused ring systems.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Jiao
authors.forename: Changxia
authors.initials: C
authors.lastname: Yuan
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Yu
mesh_terms: D001952:Bridged-Ring Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D003517:Cyclopentanes / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D000081223:Polycyclic Sesquiterpenes; D012238:Rhodium / Q000737:chemistry*; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001952:Bridged-Ring Compounds; D003517:Cyclopentanes; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C091127:1-desoxyhypnophilin; C486985:hirsutene; D012238:Rhodium