Recently, the identity of the marine hydrindane natural product (-)-mucosin was revised to the trans-fused structure 6, thereby providing a biogenetic puzzle that remains to be solved. We are now disseminating some of our insights with regard to the possible machinery delivering the established architecture. Aspects with regard to various modes of cyclization in terms of concerted versus stepwise processes are held up against the enzymatic apparatus known to be working on arachidonic acid (8). To provide a contrast to the tentative polyunsaturated fatty acid biogenesis, the structural pattern featured in (-)-mucosin (6) is compared to some marine hydrinane natural products of professed polyketide descent. Our appraisal points to a different origin and strengthens the hypothesis of a polyunsaturated fatty acids (PUFA) as the progenitor of (-)-mucosin (6).
Keywords: 7,8-disubstituted bicyclo[4.3.0]non-3-ene; Diels-Alderases; arachidonic acid metabolite; concerted vs. discrete pathways; eicosanoid motif; ene-reductases; marine hydrindane natural product; prostaglandins; tentative PUFA biogenesis; trans-fused carbocycle.