This article describes a concise synthesis of cardiotonic steroids oleandrigenin (7) and its subsequent elaboration into the natural product rhodexin B (2) from the readily available intermediate ( 8) that could be derived from the commercially available steroids testosterone or DHEA via 3 step sequences. These studies feature an expedient installation of the β16-oxidation based on β14-hydroxyl directed epoxidation and subsequent epoxide rearrangement. The following singlet oxygen oxidation of the C17 furan moiety provides access to oleandrigenin (7) in 12 steps (LLS) and 3.9% overall yield from 8. The synthetic oleandrigenin ( 7) was successfully glycosylated with L-rhamnopyranoside-based donor using Pd(II)-catalyst, and the subsequent deprotection under acidic conditions provided cytotoxic natural product rhodexin B (2) in 68% yield (2 steps). File list (2)download file view on ChemRxiv Final Manuscript.pdf (755.58 KiB) download file view on ChemRxiv Final Supporting Information Spectra.pdf (6.08 MiB)

This article describes a concise synthesis of cardiotonic steroids oleandrigenin (7) and its subsequent elaboration into the natural product rhodexin B (2) from the readily available intermediate (8) that could be derived from the commercially available steroids testosterone or DHEA via 3 step sequences. These studies feature an expedient installation of the β16-oxidation based on β14-hydroxyl directed epoxidation and subsequent epoxide rearrangement. The following singlet oxygen oxidation of the C17 furan moiety provides access to oleandrigenin (7) in 12 steps (LLS) and 3.9% overall yield from 8. The synthetic oleandrigenin (7) was successfully glycosylated with L-rhamnopyranoside-based donor using Pd(II)-catalyst, and the subsequent deprotection under acidic conditions provided cytotoxic natural product rhodexin B (2) in 68% yield (2 steps). <br>

This article describes a concise synthesis of cardiotonic steroids oleandrigenin (7) and its subsequent elaboration into the natural product rhodexin B (2) from the readily available intermediate (8) that could be derived from the commercially available steroids testosterone or DHEA via 3 step sequences. These studies feature an expedient installation of the β16-oxidation based on β14-hydroxyl directed epoxidation and subsequent epoxide rearrangement. The following singlet oxygen oxidation of the C17 furan moiety provides access to oleandrigenin (7) in 12 steps (LLS) and 3.9% overall yield from 8. The synthetic oleandrigenin (7) was successfully glycosylated with L-rhamnopyranoside-based donor using Pd(II)-catalyst, and the subsequent deprotection under acidic conditions provided cytotoxic natural product rhodexin B (2) in 68% yield (2 steps). <br>

No abstract

This chapter describes the procedure for synthesis of (((1R,3S,3'S)‐3,3'‐Diethyl‐3H,3'H‐1,1'‐spirobi[isobenzofuran]‐7,7'‐diyl)bis(oxy))bis(diphenylphosphane). It presents some of the important points to be considered, the conditions that need to be maintained, characterization data, and the reagents required, as well as the techniques used and the equipment setup that are vital to carrying out the process. The chapter also describes the hazards associated with working with chemicals and the ways to deal with these hazards. Chiral organic ligands have been of great importance for the asymmetric transition‐metal catalysis since the discovery of Noyori asymmetric hydrogenation. After many decades of research, several generally well‐performing privileged ligand scaffolds have been identified.