3,4-DICHLOROPHENYLBORONIC ACID, PINACOL ESTER synthesis

8synthesis methods

Product Name:3,4-DICHLOROPHENYLBORONIC ACID, PINACOL ESTER
CAS Number:401797-02-2
Molecular formula:C12H15BCl2O2
Molecular Weight:272.96

76-09-5 Synthesis

76-09-5
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22092-92-8
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Benzenediazonium, 3,4-dichloro-, tetrafluoroborate(1-) (1:1)

405-02-7
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3,4-DICHLOROPHENYLBORONIC ACID, PINACOL ESTER

401797-02-2
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Yield:401797-02-2 72%

Reaction Conditions:

Stage #1: diisopropopylaminoborane;1,2-dichloro-4-diazoniumbenzene tetrafluoroboratewith bis(cyclopentadienyl)titanium dichloride in acetonitrile at 20; for 2.5 h;
Stage #2: with methanol in acetonitrile at 0 - 20; for 1 h;
Stage #3: 2,3-dimethyl-2,3-butane diol in diethyl ether;acetonitrile at 20; for 4 h;Reagent/catalyst;

Steps:

33.VIA19

Example 3: General procedure D for the synthesis of the arylpinacolboronates by arylation of diisopropylaminoborane, catalysed by ferrocene (1%), followed by methanolysis and transesterification In a dried tube reactor under argon as described in example 2, the arenediazonium salt (1 mmol) and the ferrocene (ΙΟμιηοΙ, 1.8mg) were dissolved in 2mL of anhydrous CH₃CN. Diisopropylaminoborane (2mmol, 226mg) was then added to the solution and the mixture was stirred for 2h30 at room temperature. The reaction mixture was quenched by a slow addition of anhydrous MeOH at 0°C (2mL) and stirred for an additional hour at room temperature. After removal of all the volatiles, 1.3eq of pinacol was added in Et₂0 (2mL), the mixture was stirred 4h at room temperature. The crude mixture was washed with a 50g/L CuCl₂ solution (2 x 5mL). The organic layer were separated, dried over Na₂S0₄, filtered and concentrated to dryness. The resulted oil was dissolved with CH₂C1₂ and filtered of a pad of silica gel, eluting with CH₂C1₂ to afford the corresponding boronate. Example 33: Synthesis of the arylpinacolboronates by arylation of diisopropylaminoborane., catalysed by a titanocene (1%), followed by methanolysis and transesterification Compounds VI_AI to VI_A22, I_A24 and VI_A26 were prepared using the procedure D (example 3), by replacing the ferrocene (1%) by the titanocene Cp₂TiCl₂ (1%). The yields are shown in the table 1.