Zieliński A, Marset X, Golz C, Wolf LM, Alcarazo M. Two-Step Synthesis of Heptacyclo[6.6.0.0
2,6 .0
3,13 .0
4,11 .0
5,9 .0
10,14 ] tetradecane from Norbornadiene: Mechanism of the Cage Assembly and Post-synthetic Functionalization.
Angew Chem Int Ed Engl 2020;
59:23299-23305. [PMID:
32881255 PMCID:
PMC7756769 DOI:
10.1002/anie.202010766]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Indexed: 01/18/2023]
Abstract
A selective and scalable two-step approach to the dimerization of norbornadiene (NBD) into its thermodynamically most stable dimer, heptacyclo[6.6.0.02,6 .03,13 .04,11 .05,9 .010,14 ] tetradecane, (HCTD) is reported. Calculations indicate that the reaction starts with the Rh-catalyzed stepwise homo Diels-Alder cyclisation of NBD into its exo-cis-endo dimer. Treatment of this compound with acid promotes its evolution to HCTD via a [1,2]-sigmatropic rearrangement. The assemblies of 7,12-disubstituted cages from 7-(alkyl/aryl) NBDs, as well as the selective post-synthetic C-H functionalization of the core HCTD scaffold at position C1, or positions C1 and C4 are described.
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