Reactions of Achiral Carbonyl Dienophiles with Chiral Heteroatom-. substituted Dienes

2 Reactions of Achiral Carbonyl Dienophiles with Chiral Heteroatom-substituted Dienes 

Thermal cycloaddition reactions of chiral 1-alkoxy-1,3-dienes derived from carbohydrates with glyoxylates have been widely studied delivering useful results. 

The application of Lewis acids, such as the europium salt Eu(fod)3, in [4+2] cycloadditions of carbonyl compounds (e.g. glyoxylates and aldehydes) with 1-methoxy-3-trimethylsilyloxy-l,3-butadiene (Danishefsky s diene) has been intensively examined by Danishefsky et al. and employed in natural product synthesis.  

Recently excellent diastereoselectivities were observed in reactions of the latter with chiral sulfinyl-substituted furfurylaldehydes in the presence of Sm(OTf)3.  

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