Natural product synthesis three-member ring compounds

Firstly the nitro configuration in compound 1.7.85 was inversed under the base condition. Then the hydroxyl compound was oxidized by Jones antioxidant to afford ketone 1.7.88. After compound 1.7.89 generated from 1.7.88 under Rubottom oxidation, a side reaction was triggered under the hydrogenation conditions and it formed three-member ring product 1.7.90. Although the a-hydroxyl ketone part of compound 1.7.90 could be cleaved by periodic acid and reduced to lactone structure, this synthesis route was not feasible for the total synthesis of natural product. 

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