135356-71-7

Upstream product

• 38651-65-9 (1R,5S)-(+)-nopinone 
• 616-38-6 carbonic acid dimethyl ester 

Relevant academic research and scientific papers

Stereoselective syntheses and transformations of chiral 1,3-aminoalcohols and 1,3-diols derived from nopinone

A library of 1,3-difunctionalized pinane derivatives were synthesized and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. 1,3-Aminoalcohol 6a was prepared from (-)-nopinone 2 via stereoselective Mannich condensation and reduction of the resulting β-amino ketone 4. The key aminoalcohol 6a was transformed into primary, secondary and tertiary substituted aminoalcohols in order to study the effect of the substituent on catalytic activity. Starting from (-)-nopinone, cis- and trans-β-hydroxy esters 15 and 16 were prepared in a two-step stereoselective synthesis. Reduction of the hydroxy esters resulted in pinane-based 1,3-diols, while hydrolysis of the esters, followed by DCC-mediated amidation and subsequent reduction, led to cis- and trans-N-benzyl-1,3-aminoalcohols 8 and 23. trans-N-Benzyl-1,3-aminoalcohol 8 was also prepared by selective mono-debenzylation of 6a via a continuous-flow process in an H-Cube system. The resulting aminoalcohols and diols were applied as chiral catalysts in the reaction of diethylzinc and benzaldehyde.

Facial selective Diels-Alder reactions of (1R,5R)-(+)-3-carbomethoxy-6,6-dimethylbicyclohept-3-en-2-one. Unusual ketalization-fragmentation reaction of adducts

The stereofacially differentiated enone ester 5 has been used to study the effects of steric influence on the Diels-Alder reaction.In general, under Lewis acid catalysis, 5 adds to dienes at low to ambient temperatures in a reasonable rate.Yields of predictable chiral adducts are moderate with the unexpected exception of zinc chloride catalyzed reactions, which provide good to high yields.In all cases only products of addition to the Si face of general type 21 were observed.The regiochemistry of the adducts is exclusively that predicted by the ortho and para rules.The stereochemistry shows a high selectivity in favor of ester-endo transition state products.Rationales for the observed stereoselectivities are discussed.The fragmentation of adducts of 5, in particular keto ester 9, has been briefly examined.Olefins 30 and 46 derived from 9 have been converted to ring-opened cadinane skeletons 31 and 47, respectively, by conditions we have previously reported.In an entirely new and unexpected reaction, simultaneous ketalization and fragmentation of the cyclobutane ring of ketones derived from 9 gave ring-opened ketals 34 + 35 (from 29), 36 + 37 (from 9), 39 (from 38) and 42 + 43 (from 40).

Diels-alder reactions of chiral 5,5-dimethyl-4,6-methano-2-methoxycarbonyl-2-cyclohexenone

Diels-Alder reactions of the chiral enone ester 1 proceed in high yield with addition exclusively to the less hindred Si-face to give adducts of type 5.