ature gave R - in slightly higher enantioselectivity entry vs . Higher loading of R - at 0 mol% did not improve the yield or enantioselectivity entry vs; vs. An excess of acceptor to donor gave higher yield of R - entry vs. The Michael addition of and was slower ca. 0% conversion over h with sterically hindered catalysts R - or R - at 0 ° C as compared to that with R - . Therefore, reactions of and using R - or R - were carried out at room Nelarabine temperature Table . The use of larger excess of equiv resulted in higher yield entries and 7 vs. Using equiv of the , we compared the reaction of pure a Reyes, E.; Jiang, H.; Milelli, A.; Elsner, P.; Hazell, R. G.; Jørgensen
K. A. Angew. Chem., Int. Ed. 007 , , 90. b Gotoh, H.; Hayashi, Y. Org. Lett. 007 , 9 , 89 . Jacobi, P. A.; Kravitz, J. I.; Zheng, W. J. Org. Chem.99 , 0 , 7 . Org. Lett., Vol., No. 9, 009 faster reactions as illustrated by benzoic acids substituted Table. Reactions of using R - a with electron withdrawing fluoro-entries , or nitro- groups entries, , compared to Nelarabine 121032-29-9 benzoic acid entry t time yield ee . Interestingly, further increase in acidity from -ni- entrye solvent PhMe PhMe PhH PhCF PhCl cyclohex THF dioxane PhMe PhH PhMe PhH PhMe PhMe PhMe additive trobenzoic acid entry to dinitrobenzoic acids entry , resulted in lower enantioselectivities. Applying the optimized conditions entry, Table , adduct R - was obtained in 8% yield at 89% ee. R - was treated with aqueous ammonia to give the corresponding imine which was subsequently oxidized by iodine to provide the nitrile R - in 8% yield. The SEM protection group in R - was removed using LiBF and aqueous ammonia to give INCB08 in 8% yield.
The enantiomeric purity was maintained during this reaction. Using the optimized conditions for the reaction between and , we conducted the aza-Michael addition of the POM-protected 0 to aldehyde Scheme and Table . a 0. mmol scale with equiv of and. equiv of aldehyde in the presence of0 mol % of organocatalyst R - and0 mol % of acid buy Nelarabine additive in . mL of solvent. b Isolated yields. c Determined by chiral HPLC analysis of the corresponding nitrile R - , conditions: Chiralcel OD-H . × 0 mm, µ m particle size; mL/min; rt; 0 nm; mobile phase,0% v/v ethanol and 90% v/v hexanes. d Organocatalyst 0 mol % R - was used. e . equiv and equiv of aldehyde used. Table . Reactions of using . The ee of the adducts were identical and yields were similar, confirming the low reactivity of the impurity a . Under identical reaction conditions entries,,7, sterically hindered catalysts R - and R - gave higher enantioselectivity 88% ee and 90% ee respectively than R - 8% ee. The use of stronger acid additives gave Org. Lett., Vol., No. 9, 009 a with equiv of 0 and equiv of aldehyde in the presence of -0 mol % of organocatalyst and -0 mol % of -nitrobenzoic acid. b Isolated yields. c Determined by chiral HPLC analysis Chiralcel OD-H of corre- sponding nitrile R – 8 , same conditions as described in Table. d Pure aldehyde contained no a was used.
Due to the low solubility of 0 in toluene, lower yield and slower reactions entries, were observed as compared 00 Reaction condition: unless specified, all reactions were carried out on Reaction condition: all reactions were carried out on 0. mmol scale Reaction condition: all reactions were carried out on 0. mmol scale mercury BIOBUSINESS BRIEFS D E A L WAT C H Dipping into Incyte’s JAK-pot Incyte has entered into two large licensing deals for their JAK/JAK inhibitors INCB800 and INCB8. In late December 009, the worldwide rights to INCB800, which is in mid-stage trials for rheumatoid arthritis, w