title: Diastereoselective Ring-Closing Metathesis as a Means to Construct Medium-Sized Cyclic Ethers: Application to the Synthesis of a Photoactivatable Gambierol Derivative.
abstract: This paper describes a concise synthesis of six- to eight-membered α,α'-substituted cyclic ethers by exploiting diastereoselective ring-closing metathesis (RCM) of 1,4-pentadien-3-yl ether derivatives. The RCM precursors could be efficiently prepared via a vinylation of the corresponding α-acetoxy ether derivatives using divinylzinc. Diastereoselective RCM of 1,4-pentadien-3-yl ether derivatives afforded a series of six- to eight-membered α,α'-substituted cyclic ethers with moderate to good diastereoselectivity. The stereochemical consequence of the diastereoselective RCM appeared to be dependent on the structure of the ring being forged. The diastereoselectivity of six- and seven-membered cyclic ethers appeared to be largely under kinetic control irrespective of the catalyst reactivity, whereas that of an eight-membered cyclic ether could be controlled by the catalyst reactivity. Finally, the diastereoselective RCM chemistry was applied to the synthesis of a biotin-tagged photoactivatable derivative of gambierol.
authors.affiliation: Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Onodera
authors.affiliation: Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Hirota
authors.affiliation: Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Yuto
authors.initials: Y
authors.lastname: Suga
authors.affiliation: Graduate School of Agricultural Science, Tohoku University , 1-1 Tsutsumidori-amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Konoki
authors.affiliation: Graduate School of Agricultural Science, Tohoku University , 1-1 Tsutsumidori-amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Yotsu-Yamashita
authors.affiliation: Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Graduate School of Life Sciences, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Fuwa