(S)-4,4-Dichloro-3-methylbutanoic acid was prepared in 51% overall yield from commercially available starting materials using an organocatalytic transfer hydrogenation to 4,4-dichloro-3-methylbut-2-enal in the key step. The (S)-dichloro acid was used as an intermediate in the first total synthesis of dysideaproline E and a diastereomer confirming the structure of the natural product.

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In this paper, a hypothetical network is proposed for the Volta Basin System (V.B.S) using the optimization technique for obtaining corresponding optimal allocation of flows from runoffs in the sub-basins (source) to the sink (Akosombo reservoir). Maximum flow paths and their capacities with consumptive and non-consumptive flows were identified. We are able to determine the optimal withdrawals on these flows for either consumptive or non-consumptive use.

This paper discusses the levels of some heavy metals (Cu and Pb) in the soil sediments of the Kakum River, its estuary and tributaries. Samples were collected at five sites, two at the estuary of River Kakum (MZ and TZ) and the other at confluence of three of its tributaries, namely Nkontro, Kakum and Sruwe. The total Cu concentrations were found to be: Nkontro, 4.656 mg/kg > Kakum, 3.197 > Sruwe 3.16 mg/kg kg > MZ, 1.893 mg/kg > TZ, 1.277 mg. The total lead concentrations were as follows: Nkontro, 6.611 mg/kg > Kakum, 6.063 mg/kg > MZ, 3.983 mg/kg > Sruwe, 3.901 mg/kg > TZ, 3.038 mg/kg. Generally, both Cu and Pb in the sediment (residue) at the five sites follow the trend Sruwe >Kakum > TZ > MZ, while the trend for the leachate was MZ > Kakum > TZ. The levels of both metals in the leachate at site MZ were higher compared to the levels at site TZ. The contamination factors and geo-accumulation index values suggest that the sediments of the river at the selected sites were not polluted with Pb and Cu.

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