An efficient, economical, and practical Reformatsky reaction of α-halo carbonylcompounds with aldehydes/ketones by using cheap and commercial iron(0) powder as reaction mediator is developed. The reactions proceeded effectively in the presence of a catalytic amount of iodine (20 mol %) to afford the synthetically useful β-hydroxyl carbonylcompounds in moderate to good yields.
Reversal of Chemoselectivity in Organotin Lewis Acid-Catalyzed Reaction of Ketene Silyl Acetal with Aldehyde and α-Enal
作者:Jianxie Chen、Junzo Otera
DOI:10.1055/s-1997-715
日期:——
The organotin Lewis acid-catalyzed reaction of ketene silyl acetal with aldehydes results in reversal of chemoselectivity: α-enals react preferentially or exclusively in competition with an alkanal or even aromatic aldehydes.
Synthesis of β-hydroxy esters using highly active manganese
作者:YoungSung Suh、Reuben D. Rieke
DOI:10.1016/j.tetlet.2003.11.045
日期:2004.2
A modified Reformatskyreaction is reported using highly reactive manganese (Mn*). The active manganese was found to readily react with α-haloester in the presence of aldehydes and ketones to yield the corresponding β-hydroxy esters. The reaction is carried out at roomtemperature in the absence of Lewis acid or trapping agents.
hemimalonate used. With the unsubstituted substrate, a carboxylic acid intermediate was isolated upon acid quench resulting from the nucleophilic addition of the putative enol carboxylate anion of the hemimalonate to imines/aldehydes before CO2 loss. With substituted hemimalonates, the reaction likely involved an enolate which then added to imines/aldehydes or was competitively protonated. According to the base