39029-49-7

Upstream product

• 94-02-0 ethyl 3-oxo-3-phenylpropionate 
• 15186-48-8 2,3-isopropylidene-glyceraldehyde 

Downstream Products

• 143264-83-9 (R)-6-Amino-5-cyano-4-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl)-2-phenyl-4H-pyran-3-carboxylic acid ethyl ester 

Relevant academic research and scientific papers

The first asymmetric synthesis of polyfunctionalized 4H-pyrans via Michael addition of malononitrile to 2-acyl acrylates

Starting from (R)-2,3-O-isopropylideneglyceraldehyde, the first asymmetric synthesis of 4H-pyrans (4) has been developed; a detailed X-ray structural and stereochemical study has established as R the absolute configuration at the new stereocenter in compounds 4.

Michael addition of malononitrile to chiral α-acylacrylates

Starting from 2,3-O-isopropylidene-D-glyceraldehyde (1), 3-O-methyl and 3-O-benzyl-1,2-O-isopropylidene-α-D-xylo-pentodialdo-1,4-furanose (4a, 4b), we describe the synthesis of the α-acyl-β-alkyl substituted acrylates 2 and 5. The Michael addition of malononitrile to these substrates gives the polyfunctionalized 2-amino-4H-pyrans 3 and 6 with moderate diastereoselectivity and reasonable overall yield from diols 7 and 8a,b. A detailed analysis is performed scanning different type of bases in the Michael reaction. We find that, while for acceptor 2 no changes are observed, for compound 5 the stereochemical outcome of the 1,4-addition is reversed in going from piperidine, sodium hydride or potassium t-butoxide to lithium diisopropylamide or lithium diisopropylamide/magnesium iodide reagent. Several models fro rationalising the results are proposed.