Chelation-Controlled Reduction of α-Methylated 8-Oxabicyclo[3.2.1]oct-6-en-3-ones with Samarium Diiodide. Diastereoselective Preparation of Secondary Alcohols

Abstract

The title reduction has been effected with high stereocontrol using samarium diiodide in the presence of a proton source. It is concluded that chelation of samarium by the ether oxygen of the substrate directs and facilitates the reduction to equatorial alcohol.

Samarium Diiodide Mediated Reductive Addition Reaction of 1-(phenylsulfonylmethyl) Benzotriazole and 1-(Benzoyloxymethyl) Benzotriazole to Aldehydes and Ketones

“…Samarium diiodide has been wildly applied in organic synthesis as a powerful, versatile and ether-soluble one-electron transfer reductant. 12 Previous work has shown that SmI 2 can induce reductive debenzoyloxylation 13 and desulfonylation 14 successfully. However, little attention has paid to the reductive addition reactions following debenzoyloxylation and desulfonylation.…”

Structurally and Stereochemically Diverse Tetrahydropyran Synthesis through Oxidative CH Bond Activation

“…The reduction of 24 with NaBH 4 was unselective, because the alkynyl group blocks the axial approach of the hydride. In contrast, SmI 2 and iPrOH [26] provided the equatorial alcohol as a single isomer in 85 % yield. The selective reductions in this series illustrates that alkynyl substitution could be extremely useful for the synthesis of 2,6-trans-dialkyltetrahydropyran-containing natural products.…”