ChemInform Abstract: Chelation-Assisted Regioselective C—O Bond Cleavage Reactions of Acetals by Grignard Reagents. A General Procedure for the Regioselective Synthesis of Protected Polyols Having One Free Hydroxy Group.
✍ Scribed by Tien-Yau Luh; et al. et al.
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 37 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0931-7597
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✦ Synopsis
Chelation-Assisted Regioselective C-O Bond Cleavage Reactions of Acetals by Grignard Reagents. A General Procedure for the Regioselective Synthesis of Protected Polyols Having One Free Hydroxy Group.
-On treatment with Grignard reagents, acetals containing a neighboring heteroatom (N,O) undergo regioselective ring opening. The chelation plays a key role in directing the regioselectivity. This reaction offers a powerful method in selective protection-deprotection of hydroxy groups in carbohydrates leading to various saccharides which have only one free hydroxy group at a specific position. Ring opening of the acetal group at the anomeric carbon generates a hemiacetal which further reacts to a diol like (XV).