1: With tert.-butyl lithium in diethyl ether T=-95°C; 0.5 h; 2: With tri-isopropoxy-borane in diethyl ether T=-95°C; 0.333333 h; 3: With silica gel

in tetrahydrofuran react. under N2; THF cooled to -60°C, addn. of borate and Grignard reagent in THF simultaneously (equimolar amts. over whole period of react.), then stirred for 30 min at -60°C, warmed to room temp., stirred for 30 min;; treated with water, extd. with Et2O, organic layers extd. with 1M aq. NaOH, aq. layers acidified with 2M aq. HCl, extd. with CH2Cl2, organic layers dried (MgSO4), filtered, concentrated, recrystd. from water; elem. anal.;;

copper(I) thiophene-2-carboxylate; tetrakis(triphenylphosphine) palladium(0) in 1,4-dioxane T=100°C; 12 h;

air; sodium carbonate; palladium diacetate in ethanol 72 h; Ambient temperature;

1: 77 percent / 2 M aq.Na2CO3 / Pd(PPh3)4 / 1,2-dimethoxy-ethane; ethanol / 18 h / Heating 2: 1) BBr3, 2) glacial HOAc / 1) CH2Cl2, overnight, 2) reflux, 18 h View Scheme

Suzuki coupling;

tetrakis(triphenylphosphine) palladium(0); sodium carbonate in ethanol; benzene T=20°C; Suzuki coupling; 3 h;

tetrakis(triphenylphosphine) palladium(0); sodium carbonate in ethanol; benzene 18 h; Heating;

tetrakis(triphenylphosphine) palladium(0); sodium carbonate in ethanol; benzene 74 h; Heating;

air; sodium carbonate; palladium diacetate in ethanol 72 h; Ambient temperature;