A Concise Synthesis of a Trehazolamine Epimer with Moderate α-Mannosidase Inhibitory Activity Starting from d-Mannose

Abstract

A concise synthesis of a trehazolamine diastereoisomeric analog with moderate a-mannosidase inhibitory activity has been developed starting from D-mannose and using a highly stereoselective ketone-oxime ether reductive carbocyclization promoted by samarium diiodide.

Phthalimides as Exceptionally Efficient Single Electron Transfer Acceptors in Reductive Coupling Reactions Promoted by Samarium Diiodide

“…The cis relative stereochemistry of 4c was unambiguously determined by X-ray diffraction (Figure ), and those of the other products in this series were only tentatively assigned from this. The observed stereoselectivity differs from that found in the related cross-coupling of oxime ethers with aldehydes and ketones, which gives preferentially the trans product .…”

Samarium(II)-Iodide-Mediated Cyclizations in Natural Product Synthesis

“…An excess of SmI 2 was used in the cyclization of 111 such that, after cyclization, the addition of a large excess of H 2 O activated the remaining reagent, allowing reduction of the initially formed benzyloxyamine to the amine (Scheme ). In situ treatment with aqueous LiOH then removed the acetate protecting group, giving amine 112 in almost quantitative yield. ,

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Radicals and Carbohydrates

“…The Giese 160 and Chiara et al . 161 groups have described one of the most suitable methods for the synthesis of aminocyclopentitols such as 136 by SmI 2 -based reductive couplings of polyhy-droxylated oxime ethers 162 or N ,N -disubstituted hydrazones 163 in studies toward the synthesis of trehazolamine.…”