Bi(OTf)₃-Catalyzed One-Step Catalytic Synthesis of N-Boc or N-Cbz Protected α-Branched Amines

Abstract

In this paper, N-Boc and N-Cbz protected α-branched amines are synthesized directly from commercially available aromatic/heteroaromatic compounds, aldehydes, and tert-butyl or benzyl carbamate bearing a variety of substituents. Bismuth(III) triflate is found to be a highly effective catalyst for this one-pot, three-component coupling reaction. In addition, the use of mild reaction conditions, low catalytic loading, easy removal of the N-protective group, and one-step synthesis under "open-flask" are advantages of the present procedure.

Synthesis of Difurylarylmethanes Catalyzed by Bromodimethylsulfonium Bromide

“…到目前为止, 国内外文献报道的催化 2-甲基呋喃和芳香醛缩合的主 要催化剂有 Yb(OTf) 3 [7] 、AuCl 3 [8] 、B(C 6 F 5 ) 3 [9] 、RuCl 3 • 3H 2 O [10] 、 Hg(ClO 4 ) 2 、 Tl(ClO 4 ) 3 、 p-TSA [11] 、 I 2 [12] 、 Bi(OTf) 3 [13] . 尽管这些方法中有些具有很好的实用性, [13] 、 AuCl 3 [8] 、 B(C 6 F 5 ) 3 [9] 、RuCl 3 •3H 2 O [10] 、I 2 [12] 7.02 (t, J＝8.6 Hz, 2H), 5.91 (br d, J＝2.7 Hz, 2H), 5.89 (br d, J＝2.7 Hz, 2H), 5.34 (s, 1H), 2.28 (s, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ: 161. 9 , 152.6, 151.6, 135.7 , 129.9, 115.2, 108.2, 106.1, 44.3, 13.6.…”

“…9 , 152.6, 151.6, 135.7 , 129.9, 115.2, 108.2, 106.1, 44.3, 13.6. 二[(5-甲基)-2-呋喃基](4-甲氧苯基)甲烷(3e) [12] : 1 H NMR (400 MHz, CDCl 3 ) δ: 7.21 (d, J＝8.7 Hz, 2H), 6.89 (d, J＝8.7 Hz, 2H), 5.91 (br d, J＝2.3 Hz, 2H), 5.89 (br d, J＝2.3 Hz, 2H), 5.33 (s, 1H), 3.82 (s, 3H), 2.28 (s, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ: 158.5, 153.1, 151.3, 132.1, 129.3, 113.8, 107.9, 106.0, 55.2, 44.3, 13.6.…”

“…二[(5-甲基)-2-呋喃基](4-硝基苯基)甲烷(3f) [12] : 1 H NMR (400 MHz, CDCl 3 ) δ: 8.19 (d, J＝8.7 Hz, 2H), 7.43 (d, J＝8.7 Hz, 2H), 5.96 (br d, J＝3.0 Hz, 2H), 5.94 (br d, J＝3.0 Hz, 2H), 5.45 (s, 1H), 2.27 (s, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ: 152.5, 151.4, 147.9, 147.5, 129.7, 124.2, 109.3, 106.7, 45.3, 14.0. [7] : 1 HNMR (400 MHz, CDCl 3 ) δ: 8.13～8.11 (m, 2H), 7.59 (d,J＝8 Hz,2H),7.50～7.46(m,1H), 5.94～5.92 (m, 4H), 5.44 (s, 1H), 2.25 (s, 6H); 13 C NMR (100 MHz, CDCl 3 ) δ: 151. 9, 151.0, 148.3, 142.1, 134.4, 129.1, 123.2, 121.9, 108.6, 106.1, 44.5, 13.4.…”

“…2-[二(5-甲基呋喃-2-基)甲基]-5-甲基呋喃(3h) [11] : 1 H NMR (300 MHz, CDCl 3 ) δ: 2.26 (s, 9H), 5.33 (s, 1H), 5.87 (s, 3H), 5.93 (s, 3H); 13 CNMR (75 MHz, CDCl 3 ) δ: 13.6, 39.3, 106.4, 107.9, 150.8, 151.3.…”

“…二 [(5-甲基)-2-呋喃基](2-噻吩基) 甲烷(3i) [8a] : 1 H NMR (300 MHz, CDCl 3 ) δ: 2.26 (s, 6H), 5.56 (s, 1H), 5.87 (s, 2H), 5.95 (s, 2H), 6.87～6.93 (m, 2H), 7.17 (d, 1H, J＝ 4.9 Hz); 13 C NMR (75 MHz, CDCl 3 ) δ: 40. 4, 106.4, 108.1, 124.7, 125.8, 126.7, 143.4, 151.6, 152.4. 3-[二(5-甲基-2-呋喃基)甲基]-1H-吲哚(3j) [8a] : 1 H NMR (300 MHz, CDCl 3 ) δ: 2.25 (s, 6H), 5.58 (s, 1H), 5.85 (s, 2H), 5.89 (s, 2H), 6.93 (s, 1H), 7.03 (uneven triplet, 1H, J＝7.6, 7.3 Hz), 7.14 (uneven triplet, 1H, J＝7.9, 7.1 Hz), 7.28 (d, J＝8.1 Hz, 1H), 7.47 (d, J＝7.9 Hz, 1H), 7.91 (s, 1H); 13 C NMR (75 MHz, CDCl 3 ) δ: 13.7, 36.8, 106.1, 107.5, 111.1, 115.1, 119.4, 119.6, 122.0, 122.9, 126.5, 136.4, 150.9, 153.0. 四[(5-甲基)-2-呋喃基]-1, 4-二次甲基苯(3k) [8a] : 1 H NMR (300 MHz, CDCl 3 ) δ: 2.24 (s, 12H), 5.30 (s, 2H), 5.86 (s, 8H), 7.17 (s, 4H); 13 C NMR (75 MHz, CDCl 3 ) δ: 13.6, 44.7, 106.0, 108.1, 128.4, 138.6, 151.3, 152.8.…”