Aldehydes three-carbon chain elongation

Roush s three-carbon-chain elongation method applied to 2,3-0-cyclohexylidene-D-glycer-aldehyde (R)-166 is an efficient approach to D-glucitol derivatives which relies on the syn selective epoxidation of homoallylic alcohol 167 (O Scheme 65) [300,302]. 

Several s)uitheses of aminodeoxypentoses have employed a similar approach in which a three-carbon starting material is condensed with a two-carbon entity [237]. A synthetic equivalent of the glycoaldehyde anion, the dioxaborole 98 (O Scheme 46) has been used for the carbon chain elongation of aldehydes. Thus L-ribose is prepared from the addition of... 

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