Compound 2l

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Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

Prepared according to general procedure 2 outlined for compound 2a from methyl (E)-2,2-di(but-3-en-1-yl)-3-oxo-8-phenyloct-5-enoate 1l (47.5 mg, 0.134 mmol). After a reaction time of 36 h at −50 °C, the crude product was purified by column chromatography (hexane/EtOAc 98:2 to 97:3 to elute the product, then 80:20 to elute ligand 3f) to afford 2l as a colorless oil (33.0 mg, 69%, dr: 94:6, er: 95:5). Diastereomers were not separable by column chromatography.

Major diastereomer (1 S ,3a R ,5 S ,6a R): ¹H NMR (400 MHz, CDCl₃) δ 7.30–7.25 (m, 2 H, ArH_{m e t a}), 7.21–7.15 (m, 3 H, ArH_{o r t h o} + ArH_{p a r a}), 5.77 (ddt, 1 H, J = 17.1, 10.2, 6.5 Hz, CH=CH₂), 5.00 (d, 1 H, J = 17.2 Hz, CH=CH_{c i s}H_trans), 4.93 (d, 1 H, J = 10.3 Hz, CH=CH_cisH_{t r a n s}), 4.08 (d, 1 H, J = 1.9 Hz, OH), 3.72 (s, 3 H, CO₂CH₃), 2.61 (t, 2 H, J = 7.5 Hz, PhCH₂), 2.37–2.13 (m, 4 H, Ph(CH₂)₃CHCH_aH_bCH + Ph(CH₂)₃CHCH₂CH + CH_aH_bCH=CH₂ + Ph(CH₂)₃CH), 2.03–1.77 (m, 5 H, CH₂CH_aH_bCCO₂CH₃ + CH_aH_bCH=CH₂ + CH_aH_bCH₂CH=CH₂ + CH_aH_bCH₂CCO₂CH₃ + CH_aH_bCOH), 1.72–1.58 (m, 4 H, CH₂CH_aH_bCCO₂CH₃ + CH_aH_bCH₂CH=CH₂ + PhCH₂CH₂), 1.45–1.30 (m, 2 H, PhCH₂CH₂CH₂), 1.20–1.07 (m, 2 H, CH_aH_bCOH + CH_aH_bCH₂CCO₂CH₃), 0.80–0.67 (m, 1 H, Ph(CH₂)₃CHCH_aH_bCH); ¹³C NMR (100 MHz, CDCl₃) δ 178.2 (CO₂CH₃), 142.8 (C_qAr), 138.6 (CH=CH₂), 128.4 (C_{o r t h oAr}), 128.3 (C_{m e t aAr}), 125.6 (C_{p a r aAr}), 114.4 (CH=CH₂), 93.1 (COH), 58.0 (CCO₂CH₃), 52.0 (CO₂CH₃), 51.0 (CHCOH), 43.5 (CH₂COH), 42.1 (Ph(CH₂)₃CHCH₂CH), 39.4 (Ph(CH₂)₃CH), 36.2 (PhCH₂), 35.1 (CH₂CH₂CCO₂CH₃), 35.0 (PhCH₂CH₂CH₂), 33.1 (CH₂CH₂CH=CH₂), 30.4 (PhCH₂CH₂), 30.0 (CH₂CH=CH₂), 29.7 (CH₂CH₂CCO₂CH₃); IR v_max (neat/cm^-1): 3509, 2929, 2854, 1705, 1640, 1495, 1453, 1433, 1276, 1201, 1148, 1030, 995, 909, 853, 805, 747, 698, 667, 619; HRMS (APCI) calcd for C₂₃H₃₃O₃, [M+H]⁺: 357.2424, found 357.2423. [α]²²_D = +50.2 (c = 0.27, CH₂Cl₂).

Minor diastereomer (1 S ,3a R ,5 R ,6a R), diagnostic visible signals only: ¹H NMR (400 MHz, CDCl₃) δ 4.15 (d, 1 H, J = 2.1 Hz, OH); ¹³C NMR (100 MHz, CDCl₃) δ 50.9 (CO₂CH₃), 42.3 (Ph(CH₂)₃CHCH₂CH), 38.8 (Ph(CH₂)₃CH), 35.2 (CH₂CH₂CCO₂CH₃), 34.3 (PhCH₂CH₂CH₂), 30.7 (PhCH₂CH₂), 28.1 (CH₂CH₂CCO₂CH₃).

Enantiomeric purity of the product (major diastereomer) was determined by HPLC analysis (Amylose-1 column, hexane/iPrOH 98:2, flow rate = 0.5 mL/min, Ώ = 210 nm, retention time: 20.7 min (major), 30.5 min (minor); er: 95:5.