SmI2-induced cyclization of (E)- and (Z)-β-alkoxyvinyl sulfones with aldehydes

SmI2-induced reaction of (E)- and (Z)-β-alkoxyvinyl sulfones onto an aldehyde function afforded 2,6-syn-2,3-trans- and 2,6-syn-2,3-cis-tetrahydropyran-3-ols, respectively, via stereoselective cyclization. This reaction was applied to the synthesis of 2-methyl-tetrahydropyran, corresponding to the N-ring of gymnocin-A, and 2-exo-methylene-tetrahydropyran, a key intermediate for convergent synthesis of polycyclic ethers based on the Suzuki–Miyaura reaction.

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2-((2R,4aR,6S,7R,8aS)-2-Phenyl-7-((E)-2-(phenylsulfonyl)vinyloxy)-hexahydropyrano[3,2-d][1,3]dioxin-6-yl)acetaldehydeC23H24O7S[α]D24=-45.8 (c 1.00, CHCl3)Source of chirality: 2-deoxy-D-riboseAbsolute configuration: (2R,4aR,6S,7R,8aS)

Benzyledene acetal of (2R,3R,4aS,6R,7S,8aR)-7-hydroxy-6-(hydroxymethyl)-2-(phenylsulfonylmethyl)-octahydropyrano[3,2-b]pyran-3-yl acetateC25H28O8S[α]D26=-15.4 (c 1.01, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,3R,4aS,6R,7S,8aR)

2-((2R,4aR,6S,7R,8aS)-2-Phenyl-7-((Z)-2-(phenylsulfonyl)vinyloxy)-hexahydropyrano[3,2-d][1,3]dioxin-6-yl)acetaldehydeC23H24O7S[α]D24=-36.6 (c 1.00, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,4aR,6S,7R,8aS)

Benzylidene acetal of (2R,3S,4aS,6R,7S,8aR)-7-hydroxy-6-(hydroxymethyl)-2-(phenylsulfonylmethyl)-octahydropyrano[3,2-b]pyran-3-yl acetateC25H28O8S[α]D24=+0.6 (c 1.01, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,3S,4aS,6R,7S,8aR)

(2S,3R,4aS,6R,7S,8aR)-7-Hydroxy-6-(hydroxymethyl)-2-methyl-octahydropyrano[3,2-b]pyran-3-yl acetateC12H20O6[α]D23=-37.8 (c 0.95, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2S,3R,4aS,6R,7S,8aR)

(2R,3S,4aR,6S,7R,8aS)-7-(tert-Butyldimethylsilyloxy)-2-(hydroxymethyl)-6-methyl-octahydropyrano[3,2-b]pyran-3-olC16H33O5Si[α]D21=-24.2 (c 1.00, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,3S,4aR,6S,7R,8aS)

Benzylidene acetal of (2R,3S,4aR,7R,8aS)-2-(hydroxymethyl)-6-methylene-octahydropyrano[3,2-b]pyran-3,7-diolC17H20O5[α]D22=+9.6 (c 0.77, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,3S,4aR,7R,8aS)

Benzylidene acetal of (2R,3S,4aR,7R,8aS)-7-(tert-butyldimethylsilyloxy)-2-(hydroxymethyl)-6-methylene-octahydropyrano[3,2-b]pyran-3-olC23H35O5Si[α]D22=-4.1 (c 1.04, CHCl3)Source of chirality: 2-deoxy-d-riboseAbsolute configuration: (2R,3S,4aR,7R,8aS)