A synthetic approach was developed to the C1-C28 subunit of spongistatin 1 (altohyrtin A, 65). The key step was the coupling of the AB and CD spiroketal moieties via an anti-aldol reaction of aldehyde 62 and ethyl ketone 57. The development of a method for the construction of the AB spiroketal fragment is described and included the desymmetrization of C 2-symmetric diketone 10 and the differentiation of the two primary alcohols of 16. ...
[Szpilman, Alex M.; Cereghetti, Damiano M.; Manthorpe, Jeffrey M.; Wurtz, Nicholas R.; Carreira, Erick M. Chemistry - A European Journal, 2009 , vol. 15, # 29 p. 7117 - 7128]