Pseudo-Enantiomeric Carbohydrates in Stereoselective Syntheses

A number of commonly used auxiliaries are available in both enantiomeric forms, for example the proline-derived auxiliaries RAMP and SAMP [18] giving rise to the complementary stereoselecting reactions. However, many natural carbohydrates are available in only one configuration. The other enantiomer (usually the L-form) is very expensive in most cases and difficult to prepare. 

D-Arabinose can be considered as an equivalent to L-galactose, as has been demonstrated in asymmetric Strecker syntheses [19b]. 

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