Synthesis of Macrosporin and Related 9,10‐Anthraquinones by Biomimetic Polyketide Aromatization and Cyclization of 6‐Benzylresorcylates
This paper describes the synthesis of an array of 9,10-anthraquinones 2 by initial preparation of 6-benzylresorcylates 3 from oxo-dioxinone precursors 4 and their subsequent conversion to anthrones by cyclization and oxidation. Resorcylates 3 were obtained by an improved two-step procedure from oxo ester 5 and acyl chlorides 6. These methods were applied in a seven-step synthesis of the fungal natural product macrosporin (1).