Controlling benzylic functionality and stereochemistry: 2. Synthesis of the pseudopterosin aglycone

Homologation, cyclisation, and reduction converted the tetralin (2) to the hexahydrophenalenol (8), which was methylated to afford (19), via alkoxide-directed metalation. The degree of stereoselectivity resulting from reactions of (19) and congeners with allylsilane - Lewis acid combinations was markedly dependent upon substitution patterns, whereas Et2AlCN-SnCl4 produced pseudoaxial nitriles. The trimethyl nitrile (24) was elaborated to the pseudopterosin aglycone (4).