1,n-Rearrangement of allylic alcohols promoted by hot water: application to the synthesis of navenone B, a polyene natural product.

It was reported for the first time that hot water as a mildly acidic catalyst efficiently promoted 1,n-rearrangement (n = 3, 5, 7, 9) of allylic alcohols. In some cases, the rearrangement reactions joined isolated C-C double or triple bonds to generate conjugated polyene or enyne structure motifs. We used the 1,3-rearrangement reaction of an allylic alcohol in hot water as part of an attractive new strategy for construction of the polyene natural product navenone B by iterative use of a Grignard reaction, a 1,3-rearrangement of the resulting allylic alcohol, and subsequent oxidation of the rearranged product.