The stereoselective synthesis of methyl monate C 2 is described using as a key step an ene-intramolecular modified Sakurai cyclization (IMSC) reaction to prepare tetrahydropyran 5. An asymmetric allylic alkylation, followed by a cross-metathesis, enables the insertion of the right-hand side chain.
Collective Synthesis of Highly Oxygenated (Furano)germacranolides Derived from <i>Elephantopus mollis</i> and <i>Elephantopus tomentosus</i>
作者:Rémi Patouret、Ning Cham、Shunsuke Chiba
DOI:10.1002/anie.202402050
日期:2024.5.6
The collective synthesis of six (furano)germacranolides derived from Elephantopus mollis and Elephantopus tomentosus was achieved. The assembly of the highly oxygenated ten-membered ring of molephantin and tomenphantopin F was enabled by diastereoselective Barbier allylation coupled with Nozaki–Hiyama–Kishi macrocyclization. The photoinduced cycloisomerization of molephantin enabled access to four
作者:Livia van Innis、Jean Marc Plancher、István E. Markó
DOI:10.1021/ol0625785
日期:2006.12.1
The stereoselective synthesis of methyl monate C 2 is described using as a key step an ene-intramolecular modified Sakurai cyclization (IMSC) reaction to prepare tetrahydropyran 5. An asymmetric allylic alkylation, followed by a cross-metathesis, enables the insertion of the right-hand side chain.
Synthetic Study of Piericidins. I. Synthesis of the Side Chain of Piericidin B1.
The side chain of piericidin B1 having four (E)-olefinic linkages was prepared. The coupling reaction of the non-conjugated aldehyde (22) derived from 4, 4-dimethoxy-2-butanone and the sulfone (13) afforded a diastereomeric mixture of the hydroxy sulfone (27). Benzoylation of 27 followed by reductive olefin formation with sodium amalgam gave the desired all-trans-tetraene (29) possessing an (E)-C(5)-C(6) double bond, which was transformed to the alcohol (1) corresponding to the side chain of piericidin B1.