Synthetic studies of GKK1032s: the asymmetric synthesis of the decahydrofluorene skeleton via a novel cyclization of silyl enol ether and sequential retro Diels–Alder and intramolecular Diels–Alder reactions
decahydrofluorene skeleton of GKK1032s. The C-ring was constructed by intramolecular cyclization reaction between a chiral epoxide and silyl enol ether, and the dienophile moiety was introduced concurrently. In addition, the AB-rings were stereoselectively constructed using novel sequential retro Diels–Alder (DA) and intramolecularDiels–Alder (IMDA) reactions. Several further modifications of the IMDA adduct were
Enantioselective Synthesis of the Tricyclic Core of GKK1032, Novel Antibiotic Anti-Tumor Agents, by Employing an Intramolecular Diels-Alder Cycloaddition Strategy
作者:Munenori Inoue、Tadashi Katoh、Moriteru Asano
DOI:10.1055/s-2005-869843
日期:——
enantioselective synthesis of a decahydrofluorene nucleus, the tricyclic core (ABC-ring system) of GKK1032s, novel antimicrobial and anti-tumor agents, was achieved using a highly diastereoselective intramolecular Diels-Alder (IMDA) reaction. The substrate for the IMDA reaction was synthesized through intermolecular Diels-Alder reaction of Kitahara-Danishefsky's diene and an enone derived from enulose to construct
The stereocontrolled total synthesis of the C31 apocarotenoid paracentrone was achieved by sequential cross-coupling reactions using C5 boronic acid ester and iodo-substituted dienes, which were newly developed building blocks for elongation of the conjugated polyene systems at both their terminals.
An enantioselective synthesis of the fullyelaborated tricyclic decahydrofluorene core (ABC-ring system) of GKK1032s, novel antimicrobial and antitumor agents, has been accomplished for the first time by employing a highly diastereoselective intramolecular Diels−Alder (IMDA) reaction. The key substrate for the IMDA reaction was efficiently prepared through (i) an intermolecular Diels−Alder reaction
The stereocontrolled total synthesis of the allene and carbonyl conjugated apocarotenoids, paracentrone and 19-hexanoyloxyparacentrone 3-acetate, was achieved by sequential cross-coupling reactions using boronic acid ester and iodine- or tin-substituted C5 dienes, which were the building blocks for the elongation of the conjugatedpolyene systems at both terminals.