Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids.

(,)-Dimethyl tartrate acetonide in THF/HMPA undergoes deprotonation with LDA and reaction at -78 °C during 12-72 h with a range of alkyl halides, including non-activated substrates, to give single diastereomers (at the acetonide) of monoalkylated tartrates , , , , of -configuration, i.e., a stereoretentive process (13-78% yields).

Alkene protection against acid using a bromide substituent: application in a total synthesis of (-)-6,7-dideoxysqualestatin H5.

The presence of a bromide substituent, instead of a hydrogen or methyl group, on a carbon-carbon double bond, protects the alkene from addition reactions when exposed to trifluoroacetic acid. This concept is used to circumvent concomitant loss of unsaturation in a late-stage acid-catalysed 6,8- to 2,8-dioxabicyclo[3.2.