A Convenient Method for the Synthesis of (Z)-α-Fluoroacrylates: Lewis Base-catalyzed Carbonyl Fluoroolefination Using Fluoro(trimethylsilyl)ketene Ethyl Trimethylsilyl Acetal
摘要:
建立了一种非常有用的方法,可在路易斯碱催化剂存在下,从各种醛和氟(三甲基硅基)乙酮三甲基硅基缩醛中立体选择性地合成 (Z)-α-氟丙烯酸酯。由氟乙酸乙酯轻松制备的乙烯酮缩醛可在温和的条件下以高产率和优异的 Z 立体选择性生成 α-氟丙烯酸酯。
The synthesis of α-fluoroacrylates and α-bromo-α-fluoroalkenes was achieved in very good yields using aldehydes and ketones, triphenylphosphine, diethylzinc as promoter, and ethyl dibromofluoroacetate or dibromofluoromethane, respectively. A change in the addition sequence was critical in order to obtain exclusively α-fluoroacrylates in good yields.
Diethylzinc-Mediated One-Step Stereoselective Synthesis of α-Fluoroacrylates from Aldehydes and Ketones. Two Different Pathways Depending on the Carbonyl Partner
A efficient methodology allowing the one-pot stereoselective synthesis of alpha-fluoroacrylates, based on the addition of ethyl dibromofluoroacetate to a carbonyl derivative using diethylzinc as organometallic mediator, is described. Two different pathways have been identified depending on the involved carbonyl partner. In the case of aldehydes, an E2-type mechanism has been identified, whereas ketones go through an E1cb-type mechanism.