One‐Pot Stereoselective Synthesis of (Z)‐β‐Ketoenamides from β‐Halo α,β‐Unsaturated Aldehydes

Abstract

A series of steroidal and non‐steroidal β‐ketoenamides have been synthesized from their corresponding β‐halo α,β‐unsaturated aldehydes. This synthetic methodology provides efficient access to (Z)‐β‐ketoenamides. The structures of these products have been unambiguously established by single crystal XRD studies. This process is found to be mild and inexpensive. The required β‐halo α,β‐unsaturated aldehydes are synthesized from corresponding ketones using the Vilsmeier formylation reaction. One of the prepared β‐ketoenamides was transformed into its corresponding 2‐aminodihydroisoquinoline derivative.

Facile Diversity-Oriented Synthesis of Polycyclic Pyridines and Their Cytotoxicity Effects in Human Cancer Cell Lines

“…Recently, we reported the synthesis of 2-aminopyridines from β-halo-α,β-unsaturated aldehydes via Knoevenagel condensation under microwave irradiation . In addition, we have been working on β-halo-α,β-unsaturated aldehydes as a versatile synthon for various heterocycles/carbocycles . We now report this synthon for the synthesis of some novel polysubstituted pyridines using β-bromo-α,β-unsaturated aldehydes 1 {1–11}, 1,3-dicarbonyls 2 {1–8}, and ammonium acetate 3 (Figure ).…”

Cascade C–C and C–N Bond Formation: A Straightforward Synthesis of Phenanthridines and Fused Quinol­ines

“…In the context of our interest in the chemistry of β‐halo α,β‐unsaturated aldehydes,15 we report herein a cascade Suzuki cross‐coupling reaction/condensation reaction of easily accessible β‐chloro α,β‐unsaturated aldehydes15b and commercially available 2‐chloroaryl aldehydes with (2‐aminoaryl)boronic acid pinacol esters to provide quinolines and phenanthridines in excellent yields (Scheme ).…”

Mild Approach to 2-Acylfurans via Intercepted Meyer–Schuster Rearrangement of 6-Hydroxyhex-2-en-4-ynals

“…The hydroxyl aldehyde 7a was prepared following the general procedure A from bromo aldehyde (340 mg, 1.68 mmol), propargyl alcohol (169 mg, 2.0 mmol), anhydrous THF (13 mL), anhydrous i Pr 2 NH (3 mL), CuI (48 mg, 0.25 mmol), and Pd­(PPh 3 ) 2 Cl 2 (12 mg, 0.016 mmol), by stirring for 16 h at room temperature. Purification by flash chromatography (4/1 hexane/EtOAc) gave the hydroxy aldehyde 7a (330 mg, 1.60 mmol, 95%) as a pale yellow oil.…”