Pederol dibenzoate

The natural insect poison (+)-pederine (14) continues to attract interest. One useful intermediate in its synthesis, pederol dibenzoate (12), has been synthesized in several steps from (SH-)-malic acid,30 while the tetrahydropyran-2-acetamide part of pederine has been synthesized in a multistage process reduction... 

In the synthesis of pederol dibenzoate (549) (Scheme 78), diol 538 is used twice to supply the necessary chiral centers. After conversion of 538 to aldehyde 132 by routine transformations (see also Scheme 17), 132 and 538 are condensed together under acidic conditions to give dioxolan 544 as an inseparable mixture of isomers (75 25 cis/trans). 

During a synthesis of pederol dibenzoate, a key step required formation of a regiospecific enol silyl ether in a highly oxygenated and base-sensitive substrate. The reaction was uniquely achieved by a rhodium(i)-catalysed hydrosilylation sequence (Scheme 47). ... 

Willson, T.M., Kodensld, P Jarowidd, K., Isaac, K Hitchcock, P.M., Faller, A and Campbell, S.F. (1990) Studies related to the synthesis of pederin. Part 2. Synthesis of pederol dibenzoate and benzoylpedamide. Tetrahedron, 46,1767-1782. 

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See also in sourсe #XX -- [ ]

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