The synthesis of a compound suitable for the elaboration of the C-ring of nitiol

Jacqueline C. S. Woo
2004
Compound 34 was a synthetic target suitable for the elaboration to the C-ring of nitiol (1), and was synthesized over six steps from the known alcohol 39. A convenient method for the synthesis of N-methoxy-N-methyl amides was also developed. Ester 38 was synthesized from alcohol 39, and was subjected to an Ireland-Claisen rearrangement to give acid 37. This step established the stereochemical relationship of the substituents of 34. Carboxylic acid 37 was converted to amide 51 by the use of
more » ... hylamine, methanesulfonyl chloride, and N,O-dimethylhydroxylamine. This method was also used in the synthesis of seven other examples of N-methoxy-N-methyl amides with good to excellent yields (61-84 %). Amide 51 was converted to vinyl ketone 36, and subsequent ring-closing metathesis afforded cyclopentenone 35 with a cis/trans ratio of 12:1. A 1,4-hydride reduction of cyclopentenone 35 and the subsequent trapping of the enolate as a trifluoromethanesulfonate gave 34 with a cis/trans ratio of 9:1. [Chemical Diagrams]
doi:10.14288/1.0061083 fatcat:p7kqbrqea5bsvfp5qavyv3wyiq