Total synthesis of the proposed structure of the anthrapyran metabolite delta-indomycinone.
The first total synthesis of the proposed structure of delta-indomycinone has been accomplished. The key steps involve the Diels-Alder reaction of a bromonaphthoquinone (6) and 1-methoxy-3-methyl-1-trimethylsiloxy-1,3-butadiene (7) to access the anthraquinone skeleton, representing a common building block of other naturally occurring anthraquinone antibiotics, regioselective bromination of anthraquinone (14) and a highly diastereoselective alkylation of enantiomerically pure dioxolanone 8. The reported synthetic approach has the advantage of high yields, excellent selectivity and a remarkable general applicability for the total synthesis of other anthrapyran natural products. The spectroscopic data obtained for the synthetic compounds 2 and 36 are not in agreement with those reported for the natural product, and therefore revision of the assigned structure is required.
Tietze
Lutz F
LF
Institut für Organische und Biomolekulare Chemie, Georg-August-Universität, Tammannstrasse 2, Göttingen, Germany. ltietze@gwdg.de
Singidi
Ramakrishna Reddy
RR
Gericke
Kersten M
KM
D000880:Anthraquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D001688:Biological Products / Q000737:chemistry; D015394:Molecular Structure; D011714:Pyrans / Q000737:chemistry* / Q000378:metabolism; D011753:Pyrones / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism
D000880:Anthraquinones; D001688:Biological Products; D011714:Pyrans; D011753:Pyrones; C109715:delta-indomycinone