Stereoelectronic effects in the DIBAL reduction of aryl-1,2-ethanediol benzylidene acetals
β Scribed by Donald R Gauthier Jr.; Ronald H Szumigala Jr.; Joseph D Armstrong III; R.P Volante
- Book ID
- 104231518
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- French
- Weight
- 79 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0040-4039
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β¦ Synopsis
Reduction of benzylidene acetal 8 with DIBAL-H selectively gave 4 in 89% yield. 1-Aryl-1,2-diol benzylidene acetals display unusual regioselectivity with electron withdrawing groups on the aryl group.
π SIMILAR VOLUMES
Regioselectivity in the ring-opening reaction of 1,2-O-benzylidene sugars was studied. In the reductive ring-opening reaction of 1,2-O-benzylidene derivatives, only a C O1 bond was cleaved in the case of manno-type, but both the C O1 and C O2 bonds were cleaved in the case of gluco-type.
BH./Bu20T f is an effective reagent to reductively cleave 4,6-O-benzylidene acetals of various hexopyranosides to the corresponding 4-O-benzyl ethers. 4,6-O-Isopropylidene acetals can be similarly cleaved. Common protecting groups are stable to the reaction conditions.