Total Synthesis of the Labdane Diterpenes Galanal A and B from Geraniol
作者:Shih-Che Lin、Rong-Jie Chein
DOI:10.1021/acs.joc.6b02766
日期:2017.2.3
The first total synthesis of galanal A and B has been achieved from naturally occurring geraniol. Key steps in this synthesis are the use of a Lewis acid assisted chiral Brønsted acid (chiral LBA) mediated cationic polyene cyclization and a titanocene-mediated radical cyclization for the asymmetric assembly of the “AB” ring and the construction of the all-carbon quaternary center at the junction of
ZnI<sub>2</sub>/Zn(OTf)<sub>2</sub>-TsOH: a versatile combined-acid system for catalytic intramolecular hydrofunctionalization and polyene cyclization
作者:Ting-Hung Chou、Bo-Hung Yu、Rong-Jie Chein
DOI:10.1039/c9cc07242j
日期:——
combined-acid system using a zinc(II) salt [ZnI2 or Zn(OTf)2] and p-toluene sulfonic acid (TsOH) was investigated for catalytic cationic cyclizations, including intramolecular hydrocarboxylation, hydroalkoxylation, hydroamination, hydroamidation, hydroarylation and polyenecyclizations. This reaction provides easy access to five- and six-membered O- and N-containing saturated heterocyclic compounds, tetrahydronaphthalene