Enantioselective Organocatalytic Michael Addition of Aldehydes to β-Nitrostyrenes

Abstract

The utility of C(2)-symmetric bipiperidine and bimorpholine derivatives as organocatalysts in the Michael addition of enamine intermediates formed from aldehydes to nitroolefins has been demonstrated. The best results were obtained when the reaction was run in the presence of (2R,2'R)-N-iPr-bipiperidine. The products were formed via an enamine intermediate with high diastereo- and enantioselectivity with relatively short reaction times.

TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole: a theoretical and experimental study

“…Although the use of Ti(IV) in Michael-type reactions has been known for almost forty years 12 with important applications in organic synthesis, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] the number of mechanistic studies on such reactions is limited. [18][19][20][21][22][23][32][33][34][35][36][37][38][39] This study might contribute to elucidation of the trimolecular Scheme 1 TiCl 4 -promoted trimolecular condensation.…”

Stereoselective conjugate addition of ketones to alkylidene malonates using thiourea‐sulfonamide organocatalyst

“…[1][2][3][4] Useful synthetic intermediates can be produced by selecting the combination of different Michael donors and acceptors. The organocatalytic reactions of Michael donors such as aldehydes and ketones with electron deficient Michael acceptors such as α,β-unsaturated aldehydes, 5,6 ketones, 7-10 sulfones, 11,12 and nitrostylenes [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] are well investigated. However, alkylidene malonates are rarely used as a Michael acceptor in organocatalysis despite their availability as a synthetic intermediate for access to remarkable pharmaceutical compounds.…”

Asymmetric organocatalyzed Michael addition of aldehydes to β-nitrostyrene in ionic liquids

“…N-Isopropylbipiperidine was found to be the most efficient catalyst, affording products in high diastereo-(up to 94:6) as well as enantioselectivities (up to 96%). 9 Recently, also other types of organocatalysts have been introduced for the Michael addition of aldehydes to nitroalkenes. Palomo described highly enantioselective trans-4-hydroxyprolylamides.…”