The first synthesis of the novel 2,8-dioxabicyclo[3.2.1]octane ring system: a key feature of the squalestatins
Abstract
The lithium enolate of the acetonide of (S,S)-dimethyl tartrate 5 was prepared by treatment with lithium diisopropylamide in the presence of 12-crown-4, and added to acetonylacetone 6; reaction of the product with acid gave a mixture of cyclised adducts from which a single diastereoisomer was isolated and shown to have a structure consistent with the core of squalestatin.