Zhang, Liming Koreeda, Masato Stereocontrolled Synthesis of Kelsoene by the Homo-Favorskii Rearrangement (±)-Kelsoene (<b>4</b>) has been synthesized from 2,5-dihydroanisole in 16 steps in 12.5% overall yield. The key step involves a base-catalyzed reaction of γ-keto tosylate (<b>5</b>), which effects a homo-Favorskii rearrangement to <b>16</b> as well as the corresponding intramolecular S<sub>N</sub>2 product <b>15</b> from the enolate of <b>5</b>. Ketone <b>15</b> can efficiently be isomerized to cyclobutanone <b>17</b> having the kelsoene carbon skeleton upon acid treatment. 16 steps;Ketone 15;isomerized;enolate;intramolecular S N 2 product 15;Kelsoene;acid treatment;Stereocontrolled Synthesis;cyclobutanone 17;tosylate;Rearrangement;dihydroanisole;keto;kelsoene carbon skeleton;rearrangement 2002-09-18
    https://acs.figshare.com/articles/journal_contribution/Stereocontrolled_Synthesis_of_Kelsoene_by_the_Homo-Favorskii_Rearrangement/3744264
10.1021/ol026739q.s001