Facile stereoselective synthesis of (E)- and (Z)-α-substituted cinnamates: stereospecific dehydration reaction with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and copper(II) chloride

Novel Tandem Reaction for the Synthesis of N′‐Substituted 2‐Imino‐1,3‐oxazolidines from Vicinal (sec‐ or tert‐)Amino Alcohol of Desosamine

“…To decrease the EDC excess that is required, we examined the effect of the addition of CuCl 2 as co-reagent, the combination of which has previously been used in dehydration reactions, [15] to our model synthesis of 10-12. To our surprise, we found that even 2 equiv.…”

“…Our desire to optimize this method for the larger-scale production of 2Ј,3Ј-NЈ-substituted 2-imino-1,3-oxazolidines led to the discovery of a very interesting tandem reaction of the vicinal tert-amino alcohol of the desosamine. To decrease the EDC excess that is required, we examined the effect of the addition of CuCl 2 as co-reagent, the combination of which has previously been used in dehydration reactions, [15] to our model synthesis of 10-12. To our surprise, we found that even 2 equiv.…”

Total Synthesis of Schilancitrilactones B and C

“…Methylation of 23 with NaH and CH 3 Ip rovided the compound 24 in 90 % yield with 4:1d iastereoselectivity at C13, and was then subjected to decarboxylation mediated by NaBr to produce a1:1 mixture of the lactone 25 in 88 %yield. [14] Thestructure of the E isomer was confirmed by X-ray crystallographic analysis.T hen we investigated the intramolecular radical cyclization to form the seven-membered ring. Deprotection of 26 was achieved using trifluoroacetic acid and gave the acid 27 in 93 %y ield (two steps).…”

Collective Synthesis of Schilancidilactones A, B and Schilancitrilactones A, B, C, 20‐epi‐Schilancitrilactone A

“…After optimization, we treated alcohol 25 with CuCl 2 and EDC in toluene under 80 °C (Scheme 6) to give the dienes 29 in 83% yield. [24] 1 H NMR analysis showed that the 1,3-dienes 29 were a mixture of two inseparable isomers. Fortunately, the structure of 29b was confirmed by X-ray crystallographic analysis.…”