Asymmetric synthesis of the benzoquinoid ansamycin antitumor antibiotics: total synthesis of (+)-macbecin
摘要:
A convergent asymmetric synthesis of the antitumor antibiotic macbecin I has been achieved. Six of the seven stereogenic centers within the target structure were controlled using asymmetric aldol methodology, while the final stereogenic center was established through internal asymmetric induction. Fragment coupling was accomplished using a mild, titanium tetrachloride mediated aldol reaction. The C1-C5 unsaturated dienic ester was stereoselectively incorporated through a kinetically controlled Horner-Emmons olefination. Macrolactamization and subsequent refunctionalization afforded macbecin I.
Asymmetric synthesis of the benzoquinoid ansamycin antitumor antibiotics: total synthesis of (+)-macbecin
摘要:
A convergent asymmetric synthesis of the antitumor antibiotic macbecin I has been achieved. Six of the seven stereogenic centers within the target structure were controlled using asymmetric aldol methodology, while the final stereogenic center was established through internal asymmetric induction. Fragment coupling was accomplished using a mild, titanium tetrachloride mediated aldol reaction. The C1-C5 unsaturated dienic ester was stereoselectively incorporated through a kinetically controlled Horner-Emmons olefination. Macrolactamization and subsequent refunctionalization afforded macbecin I.
作者:David A. Evans、Scott J. Miller、Michael D. Ennis、Paul L. Ornstein
DOI:10.1021/jo00030a006
日期:1992.2
The asymmetric synthesis of macbecin I is described wherein the absolute stereochemical relationships were established through the use of chiral boron aldol bond constructions and internally directed alpha-methoxy ketone reduction, while the E,Z dienic amide moiety was installed in one step using a vinylogous phosphonate reagent.
Asymmetric synthesis of the benzoquinoid ansamycin antitumor antibiotics: total synthesis of (+)-macbecin
作者:David A. Evans、Scott J. Miller、Michael D. Ennis
DOI:10.1021/jo00054a035
日期:1993.1
A convergent asymmetric synthesis of the antitumor antibiotic macbecin I has been achieved. Six of the seven stereogenic centers within the target structure were controlled using asymmetric aldol methodology, while the final stereogenic center was established through internal asymmetric induction. Fragment coupling was accomplished using a mild, titanium tetrachloride mediated aldol reaction. The C1-C5 unsaturated dienic ester was stereoselectively incorporated through a kinetically controlled Horner-Emmons olefination. Macrolactamization and subsequent refunctionalization afforded macbecin I.