Biotransformation of clovane derivatives. Whole cell fungi mediated domino synthesis of rumphellclovane A

Here we describe the biotransformation of clovane derivatives by filamentary fungi Pestalotiopsis palustris and Penicillium minioluteum, and the application of the latter to the synthesis and determination of the absolute configuration of rumphellclovane A (2). Methoxyclovanol (1), a growth inhibitor of the phytopathogen Botrytis cinerea, is metabolised by P. palustris to yield rumphellclovane A (2), a natural compound recently isolated from the gorgonian coral Rumphella antipathies, two new compounds, (1R,2S,5S,8R,9S,10R)-2-methoxyclovane-9,10-diol (5) and (1S,2S,5S,7R,8R,9R)-2-methoxyclovane-7,9-diol (6), hydroxylated in positions not easily accessed by classic synthetic chemistry, and clovanodiols 3 and 4. P. minioluteum is able to selectively transform methoxyclovanol (1) into clovanodiols 3 and 4 and, in turn, lactone 8, the putative intermediate in the above mentioned synthesis of rumphellclovane A (2), into compound 2 via a domino process. The ability of P. minioluteum to carry out the cleavage of ethers on clovane derivatives is also evaluated.