Actinobolin

Intramolecular C-acylation.1 In a synthesis of (+ )-actinobolin 4, an antibiotic from S. griseovirides, the final carbon atom was introduced by O-acylation... 

Scheme 12.38. Synthesis of actinobolin using a three-component conjugate addition/aldol condensation, by Chida and co-workers [135] TBS = t-butyldimethylsilyl, Bn = benzyl, PMB = p-methoxybenzyl.

Ttoo groups employed the p-methylbenzylsulfonyl group299 for the synthesis of the antibiotic Actinobolin.300 301 In the synthesis by Weinreb and co-workers [Scheme 8.125],300 deprotection of a single amino function took place on treatment of a p-methylbenzylsulfonamide with neat anhydrous HF in the presence of anisole. A more convenient procedure employs 70% HF in pyridine containing 2 equivalents of anisole34 2 to accomplish the deprotection of a mesitylene-sulfonamide.303... 

Tetrodotoxin Trigonelline Tylocrebrine Tylocrepine Tylophorine Xestoaminol A, C Antibiotics Actinobolin Actinomycin Amphotericin B Bacitracin Bleomycin... 

Easily prepared from glycols, enones have been investigated as dienophiles. They react with butadiene under Lewis acid catalysis to form chiral cyclohexenes used in the synthesis of compactin analogs [353]. Levoglucosenone has been used in a Diels-Alder reaction with acetoxy-butadiene to construct a part of the indole alkaloid reserpine [354], and in synthetic studies toward tetrodotoxin [355]. Analogs of the anthracycline rhodomycinone have been similarly prepared [356]. [4 + 2]-Cycloaddition of the same enone with silyloxydiene allowed the creation of the fused ring system present in actinobolin [357]. 

Recently the Ferrier-II rearrangement was used as a key step in the synthesis of unnatural (-) actinobolin. The 5,6-unsaturated compound 72 was prepared by a base-induced elimination of HI from the 6-deoxy-6-iodo-derivative 71 (O Scheme 31) [69]. 

Weinreb has reported the total syndieses of (+)-actinobolin and (-)-bactobolin from common intermediate (21). Both the reductive cleavage and Grignard addition proceeded in high overall yield (equation 11). ... 

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