Synthesis of cyclization precursors 42 a/b, 54, 55, 64 and 65. Reagents and conditions: a) BnOCH2PPh3Cl, n‐BuLi, THF, −78 °C to 22 °C; b) NEt3 ⋅ 3HF, MeCN, 22 °C, 72 % over two steps; c1) MsCl, NEt3, CH2Cl2, 0 °C to 22 °C, then TBAI, benzene, 80 °C, 41 % of 41 a/b (1 : 1); c2) I2, PPh3, imH, CH2Cl2, 0 °C, inseparable mixture of 41 b with PPh3; c3) I2, pol−PPh3, imH, CH2Cl2, 0 °C to 22 °C, 9 % of 41 a/b (1 : 6); c4) DEAD, PPh3, LiI, THF, 0 °C, 59 %; c5) DEAD, PPh3, LiI, THF, 0 °C, 80 %; d) t‐BuLi, B‐methoxy‐9‐BBN, THF, −78 °C to 22 °C, then 19, SPhos Pd GII, SPhos, Cs2CO3, DMF, H2O, 40 °C, 53 % of 42 a, 74 % of 42 b; e) EtAlCl2, CH2Cl2, −78 °C; f) SnCl4, CH2Cl2, −78 °C; g1) 44, MeMgBr, Ni(acac)2, AlMe3, THF, 22 °C; g2) 44, AlMe3, Cp2ZrCl2, CH2Cl2, 0 °C to 22 °C; g3) 46, AlMe3, Cp2ZrCl2, CH2Cl2, 0 °C to 22 °C; g4) 49, AlMe3, Cp2ZrCl2, CH2Cl2, 22 °C to 40 °C, traces; g5) 49, AlMe3, Cp2ZrCl2, H2O, CH2Cl2, −40 °C to 40 °C, 40 %; h) I2, PPh3, imH, CH2Cl2, 0 °C, 60 %; i) t‐BuLi, B‐methoxy‐9‐BBN, THF, −78 °C to 22 °C, then 52 or 53, SPhos Pd GII, SPhos, Cs2CO3, DMF, H2O, 40 °C, 88 % of 54, 60 % of 55; j) EtAlCl2, CH2Cl2, −78 °C; k) SnCl4, CH2Cl2, −78 °C; l1) t‐BuLi, CuCN ⋅ 2LiCl (10 mol%), allyl bromide, THF, −78 °C, 60/61/62 (7 : 3 : 1) determined by 1H NMR analysis of the crude reaction mixture; l2) t‐BuLi, CuCN ⋅ 2LiCl (10 mol%), allyl iodide, THF, −78 °C, 60/61/62 (10 : 10 : 1) determined by 1H NMR analysis of the crude reaction mixture; l3) i‐PrMgBr, n‐BuLi, CuCN ⋅ 2LiCl (10 mol%), allyl bromide, THF, −78 °C to 0 °C, 60/61/62 (25 : 1 : 3) determined by 1H NMR analysis of the crude reaction mixture, 66 % of 60; m) PPTS, MeOH, 22 °C, 85 %; n) I2, PPh3, imH, CH2Cl2, 0 °C, 78 %; o) t‐BuLi, B‐methoxy‐9‐BBN, THF, −78 °C to 22 °C, then 19 or 53, SPhos Pd GII, SPhos, Cs2CO3, DMF, H2O, 40 °C, 63 % of 64, 79 % of 65; p) EtAlCl2, CH2Cl2, −78 °C, traces. Acac=acetylacetone, B‐methoxy‐9‐BBN=9‐methoxy‐9‐borabicyclo[3.3.1]nonane, Bn=benzyl, Cp=cyclopentadienyl, DEAD=diethyl azodicarboxylate, DMF=N,N‐dimethylformamide, imH=imidazole, MsCl=methanesulfonyl chloride, n.d.=not determined, pol−PPh3=diphenylphosphino−polystyrene, PPTS=pyridinium p‐toluenesulfonate, py=pyridine, SPhos=2‐dicyclohexylphosphino‐2′,6′‐dimethoxybiphenyl, SPhos Pd GII=chloro(2‐dicyclohexylphosphino‐2′,6′‐dimethoxy‐1,1′‐biphenyl)[2‐(2′‐amino‐1,1′‐biphenyl)]palladium(II), TBAI=tetrabutylammonium iodide, TBS=t‐butyldimethylsilyl, Tf=trifluoromethanesulfonyl, THF=tetrahydrofuran, THP=tetrahydropyranyl.