Palladium-Catalyzed Heteroannulation Leading to Heterocyclic Structures with Two Heteroatoms: A Highly Regio- and Stereoselective Synthesis of (<i>Z</i>)-4-Alkyl-2-alkyl(aryl)idene-3,4-dihydro-2<i>H</i>-1,4-benzoxazines and (<i>Z</i>)-3-Alkyl(aryl)idene-4-tosyl-3,4-dihydro-2<i>H</i>-1,4-benzoxazines
作者:Nitya G. Kundu、Gopeswar Chaudhuri、Anup Upadhyay
DOI:10.1021/jo000826j
日期:2001.1.1
triethylamine at room temperature to yield 2-[N-alkyl(benzyl)-N-(3-aryl-prop-2'-ynyl)]-aminophenyl tosylates 8 in extremely good yields (72-96%). The latter could then be cyclized with KOH in ethanol-water to Z-9 in a highly regio- and stereoselective manner. Similarly, palladium-copper-catalyzed reaction of 2-(prop-2'-ynyloxy)aniline (21) with aryl iodides 7 led to 22-26 which after tosylation and cyclization
已开发出一种非常方便的方法来合成(Z)-4-烷基-2-烷基(芳基)亚烷基-3,4-二氢-2H-1,4-苯并恶嗪9和(Z)-3-烷基(芳基)亚烷基-4-甲苯基-3,4-二氢-2H-1,4-苯并恶嗪34-38通过钯-铜催化反应。在(PPh3)2PdCl2(3 mol%),CuI(5 mol%)在三乙胺中的存在下,芳基卤化物7与2- [N-烷基(苄基)-N-丙-2'-炔基]氨基苯基甲苯磺酸酯6反应室温下以极好的收率(72-96%)产生2- [N-烷基(苄基)-N-(3-芳基-丙-2'-炔基)]-氨基苯基甲苯磺酸酯8。然后可以在乙醇-水中用KOH以高度区域选择性和立体选择性的方式将后者环化成Z-9。类似地,钯-铜催化的2-(prop-2' -炔氧基苯胺(21)与芳基碘化物7生成22-26,在甲苯磺酸和CH3CN中,在K2CO3和Bu4-NBr存在下,用碘化亚铜环化后,生成(Z)-3-烷基(芳基)亚烷基-