Synthesis and Epoxidation of Flav-3-enes as Methodology for the Biomimetic Preparation of Flavan-3,4-diols.

SP 1 sp H NMR (600 MHz, acetone- I d i SB 6 sb + D SB 2 sb O): = 7.09 (d, I J i = 1.94 Hz, 1 H, H-2'), 7.02 (dd, I J i = 1.94, 8.22 Hz, 1 H, H-6'), 6.94 (d, I J i = 8.22 Hz, 1 H, H-5), 6.13 (d, I J i = 2.27 Hz, 1 H, H-6), 5.97 (d, I J i = 5.97 Hz, 1 H, H-8), 4.91 (d, I J i = 10.26 Hz, 1 H, H-2), 4.86 (d, I J i = 3.69 Hz, 1 H, H-4), 3.84 (dd, I J i = 3.69, 10.26 Hz, 1 H, H-3), 3.813 (s, 3 H, 5-OCH SB 3 sb ), 3.806 (s, 6 H, 3', 5'-OCH SB 3 sb ), 3.73 (s, 3 H, 7-OCH SB 3 sb ). SP 13 sp C NMR (151 MHz, CDCl SB 3 sb ): = 159.9 (C-4'), 153.7 (C-7), 149.5 (C-8a), 137.8 (C-8), 130.1 (C-1'), 128.8 (C-2', 6'), 125.3 (C-5), 114.6 (C-4a), 114.1 (C-3', 5'), 109.2 [ I C i (CH SB 3 sb ) SB 2 sb ], 106.4 (C-6), 77.7 (C-2), 75.9 (C-3), 71.6 (C-4), 61.1 (4'/8-OCH SB 3 sb ), 56.4 (7-OCH SB 3 sb ), 55.4 (4'/8-OCH SB 3 sb ), 28.6 (CH a/b), 26.1 (CH SB 3 sb a/b). SP 13 sp C NMR (151 MHz, CDCl SB 3 sb ): = 169.0 [3/2"/4"/6"-O I C i (O)CH SB 3 sb ], 168.5 [3/2"/4"/6"-O I C i (O)CH SB 3 sb ], 168.4 [3/2"/4"/6"-OC(O)CH SB 3 sb ], 167.8 [3/2"/4"/6"-OC(O)CH SB 3 sb ], 160.3 (C-5/7), 159.1 (C-5/7), 156.5 (C-8a), 149.8 (C-1'), 149.7 (C-3'/4'), 149.0 (C-3'/4'), 148.8 (C-2"/6"), 148.6 (C-2"/6"), 129.1 (C-4"), 124.0 (C-1"), 120.7 (C-6'), 114.6 (C-3"/5"), 113.4 (C-3"/5"), 111.0 (C-5'), 110.8 (C-2'), 105.5 (C-4a), 94.2 (C-6/8), 93.9 (C-6/8), 80.5 (C-2), 72.7 (C-3), 56.1 (3'/4'-OCH SB 3 sb ), 56.0 (3'/4'-OCH SB 3 sb ), 55.6 (5/7-OCH SB 3 sb ), 55.5 (5/7-OCH SB 3 sb ), 36.7 (C-4), 21.3 [3/2"/4"/6"-OC(O) I C i H SB 3 sb ], 21.2 [3/2"/4"/6"-OC(O) I C i H SB 3 sb ], 20.7 [3/2"/4"/6"-OC(O) I C i H SB 3 sb ], 20.4 [3/2"/4"/6"-OC(O) I C i H SB 3 sb ]. [Extracted from the article]