Synthesis of (E)-α-Ethynyl-α,β-unsaturated Esters from Allenyl Acetates Catalyzed by DABCO and Their Application to Sonogashira Cross-Coupling Reactions
作者:Hyun-Seok Kim、Doo-Sup Shin、Kwang-Moo Lee、Sang-Kyu Lee、Sang-Hyuk Kim、Phil-Ho Lee
DOI:10.5012/bkcs.2010.31.03.742
日期:2010.3.20
esters from another precursor without the use of (Z)-α-halo-α,β-unsaturated esters. As part of our continuing studies into the utility of allene groups, we report herein the preparation of the selective synthesis of (E)-α-ethynyl-α,β-unsaturated esters from allenyl acetates catalyzed by DABCO and their application to Sonogashira cross-coupling reaction (Scheme 1). First, various allenyl acetates were
1 PPTS (0.2) CH2Cl2 6 0 2 AcOH (0.2) DMF 12 0 3 吡啶 (0.2) DMF 0.67 75 4 PPh3 (0.2) DMF 0.5 69 5 DABCO (0.2) DMF 0.5 75 6 DABCO (0.2) THF 4.5 50 7 DABCO (0.2) CH3CN 4.5 70 8 DABCO (0.1) DMF 2.5 81 由于 α-乙炔基-α,β-不饱和酯的合成是有机合成化学中具有挑战性的问题之一,许多有效的合成方法已被用于制备这些化合物。报道。然而,仍然需要一种高选择性的 (E)-α-乙炔基-α,β-不饱和酯合成方法。通常,这些化合物的选择性合成是通过过渡金属催化的(Z)-α-卤代-α,β-不饱和酯与末端炔烃的交叉偶联反应通过Sonogashira交叉偶联反应完成的。然而,该方法受到限制,因为 (Z)-α-halo-α 的