Hydroazulene mesylates

The past few years have witnessed a considerable effort by several research groups to effect stereoselective syntheses of appropriately substituted hydroazulenes. Recently some new approaches to this problem have been reported. Marshall and Huffman, for instance, have found that treatment of the enone-mesylate (395) with diborane followed by base-induced fragmentation of the intermediate boronate (396) yielded the cyclodecadienol (397) in 60 % yield. Solvolysis of the p-nitrobenzoate of (397) in aqueous dioxan containing sodium bicarbonate afforded the hydroazulenol (398) in 70 % yield. The high degree of stereoselectivity in this reaction is rationalized on the basis of the preferred mode of cyclization of the allylic cation (399). To date, the solvolytic routes to hydroazulenes have... 

Solvolysis of the bicyclic mesylate (69) gave a mixture of rearranged olefins which were hydrogenated to give the hydroazulene (70). Oxyallyl cations react with phosphole sulphides and phosphole oxides to give the expected 8-phosphabicyclo [3,2,l]octanoic systems together with other products. ... 

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