Stereoselective 1,4-Addition of Thiols to (2E)-4,6-Di-O-acetyl-2,3-dideoxy-aldehydo-D-erythro-hex-2-enose.

Glycal-Derived δ-Hydroxy α,β-Unsaturated Aldehydes (Perlin Aldehydes): Versatile Building Blocks in Organic Synthesis

“…Lau et al demonstrated the synthesis of 3-alkylthio-2,3-dideoxy-arabino-hexopyranose 390 that involved a thermodynamically controlled 1,4-addition of 2-methyl-2-propanethiol or ethanethiol to the Perlin aldehyde 1 in the presence of DBU to obtain 389 , followed by deprotection of its acetyl groups with sodium methoxide (Scheme ) . They performed 1,4-addition of 2-methyl-2-propanethiol to enal 57 to ascertain whether the stereoselective formation of 389 was of thermodynamic origin.…”

“…Lau et al demonstrated the synthesis of 3-alkylthio-2,3-dideoxyarabino-hexopyranose 390 that involved a thermodynamically controlled 1,4-addition of 2-methyl-2-propanethiol or ethanethiol to the Perlin aldehyde 1 in the presence of DBU to obtain 389, followed by deprotection of its acetyl groups with sodium methoxide (Scheme 62). 82 They performed 1,4-addition of 2methyl-2-propanethiol to enal 57 to ascertain whether the stereoselective formation of 389 was of thermodynamic origin. As expected, the 1,4-adduct of 57 did not undergo ring closure, and a nearly 1:1 mixture containing the ribo and arabino isomers of 391 was obtained, confirming that the stereoselective formation of 389 must be reversible and thermodynamically controlled.…”