69805-60-3Relevant academic research and scientific papers
Remarkable control of radical cyclization processes of cyclic enyne: Total syntheses of (±)-methyl gummiferolate, (±)-methyl 7β-hydroxykaurenoate, and (±)-methyl 7-oxokaurenoate and formal synthesis of (±)-gibberellin A12 from a common synthetic precursor
Toyota,Yokota,Ihara
, p. 1856 - 1861 (2001)
Total syntheses of (±)-methyl gummiferolate (13b), (±)-methyl 7β-hydroxykaurenoate (14b), and (±)-methyl 7-oxokaurenoate (14d) and a formal synthesis of (±)-gibberellin A12 (15) have been accomplished through the common synthetic precursor, (3aR*,7aR*)-3,3-dimethyl-7a-(2-propynyl)-3a,4,7,7a- tetrahydroisobenzofuranone (16). The homoallyl - homoallyl radical rearrangement reaction of the monocyclic enyne 25, derived from 16 in two steps, afforded the bicyclo[2,2,2]octane compound 26, which was converted to (±)-methyl gummiferolate (13b). In contrast, the radical cyclization of the bicyclic enyne 16 gave the tricyclic lactone 19, leading to (±)-methyl 7β-hydroxykaurenoate (14b) and (±)-methyl 7-oxokaurenoate (14d). Transformation of 14d into lactone 20 was carried out in a single step under bromination conditions. This constitutes a formal total synthesis of gibberellin A12 (15).
