(R)-(+)-Methyl-CBS-oxazaborolidine
(R)-2-Methyl-CBS-oxazaborolidine
CAS: 112022-83-0
Molecular Formula: C18H20BNO
(R)-(+)-Methyl-CBS-oxazaborolidine - Names and Identifiers
(R)-(+)-Methyl-CBS-oxazaborolidine - Physico-chemical Properties
| Molecular Formula | C18H20BNO |
| Molar Mass | 277.17 |
| Density | 0.95g/mLat 25°C |
| Melting Point | 85-95°C(lit.) |
| Boling Point | 111°C |
| Flash Point | 40°F |
| Water Solubility | Not miscible or difficult to mix in water. |
| Vapor Presure | 0mmHg at 25°C |
| Appearance | Liquid |
| Color | Colorless to amber |
| Exposure Limit | ACGIH: TWA 20 ppmOSHA: Ceiling 300 ppm; TWA 200 ppmNIOSH: IDLH 500 ppm; TWA 100 ppm(375 mg/m3); STEL 150 ppm(560 mg/m3) |
| BRN | 9059874 |
| pKa | 1.02±0.40(Predicted) |
| Storage Condition | room temp |
| Sensitive | Air & Moisture Sensitive |
| Refractive Index | 68 ° (C=1, MeOH) |
| Physical and Chemical Properties | Melting point 85-95°C(lit.) boiling point 111°C density 0.95g/mL at 25°C refractive index 68 ° (C = 1, MeOH) flash point of 40 f Storage Conditions 2-8 C sensitivity Air & motion Sensitive BRN 9059874 |
(R)-(+)-Methyl-CBS-oxazaborolidine - Risk and Safety
| Risk Codes | R11 - Highly Flammable R38 - Irritating to the skin R48/20 - R63 - Possible risk of harm to the unborn child R65 - Harmful: May cause lung damage if swallowed R67 - Vapors may cause drowsiness and dizziness R36/37 - Irritating to eyes and respiratory system. R19 - May form explosive peroxides R40 - Limited evidence of a carcinogenic effect |
| Safety Description | S36/37 - Wear suitable protective clothing and gloves. S62 - If swallowed, do not induce vomitting; seek medical advice immediately and show this container or label. S33 - Take precautionary measures against static discharges. S29 - Do not empty into drains. S16 - Keep away from sources of ignition. S2 - Keep out of the reach of children. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. |
| UN IDs | UN 1294 3/PG 2 |
| WGK Germany | 3 |
| FLUKA BRAND F CODES | 10 |
| HS Code | 29319090 |
| Hazard Class | 3 |
| Packing Group | II |
(R)-(+)-Methyl-CBS-oxazaborolidine - Reference Information
| Introduction | CBS-oxazole borane catalyst (R)-2-methyl-CBS-oxazolboridine is an important chiral catalyst in the asymmetric reduction reaction, it is widely used in the synthesis of chiral ligands and chiral intermediates, bioactive substances and natural substances in the field of asymmetric synthesis, and has great market potential. |
| preparation method | Step 1: Add L-proline (115g,1mol), triethylamine (253g,2.5mol) and dichloromethane (1600mL) were cooled to -5 °c to 5 °c, and chlorotrimethylsilane (239g,2.2mol) was added dropwise, after 650ml of toluene is added, triethylamine hydrochloride produced in the reaction process is filtered out, and the filtrate is evaporated to dryness and then directly used for the next reaction. Step 2: add the product of the first step to 850ml of tetrahydrofuran, cool to -10 °c to 0 °c, slowly add 2m phenyl magnesium chloride (1.1L,2.2mol) Dropwise, After the reaction, add 15% hydrochloric acid aqueous solution to adjust PH = 1-2, filter the resulting off-white solid, add 15% sodium hydroxide to adjust PH = 10-12, extract with dichloromethane (1500mL) for four times, combine the organic layer, dry over anhydrous magnesium sulfate, distill the organic layer, slurry it in 99.2% n-heptane, and filter it to obtain 200g of white crystalline solid S-diphenylprolinol, HPLC: after dissolving the above S-diphenylprolinol (200g,0.79mol), adding dichloromethane (1800mL) and triethylamine (177g,1.75mol), control the reaction temperature -10 ℃ to 0 ℃, slowly add boron tribromide (0.82g, mol), The reaction liquid is distilled dry, and 820ml of toluene is added to filter out the reaction to generate triethylamine hydrobromide, and the filtrate is evaporated to dryness and then directly used for the next reaction; Step 4: add the product of step 3 above to diethoxymethane, cool to -10 °c to 0 °c, slowly add 3.0m methyl lithium (283mL,0.85mol) in diethoxymethane solution Dropwise, add acetic acid at the end of the reaction and neutralize, distill the solvent to dryness, after adding 840ml of n-heptane, heating up to reflux, distilling out about 40-50ml of n-heptane, filtering with closed diatomite while hot, and cooling the filtrate to -10 ℃ to 0 ℃ under the protection of inert gas, white crystals were precipitated after stirring, and 169g of product (R)-2-methyl-CBS-oxazole borane was obtained after closed filtration. The total yield of four steps was 61%,GC:98.3%,HNMR:>97%, ML of toluene was added to prepare a 1m toluene solution. |
| Use | CBS-oxazole borane catalyst (R)-2-methyl-CBS-oxazolboridine is an important chiral catalyst in the asymmetric reduction reaction, it is widely used in the synthesis of chiral ligands and chiral intermediates, bioactive substances and natural substances in the field of asymmetric synthesis, and has great market potential. CBS (Corey-Bakshi-Shibata) oxazole boridine catalysts have been used for the asymmetric reduction of prochiral ketones. Other applications include enantioselective synthesis of α-hydroxy acids, α-amino acids, C2-symmetric ferrocenediols, and propargyl alcohols. It is a kind of CBS catalyst. The catalysts can reduce prochiral ketones to the corresponding chiral secondary alcohols with high stereoselectivity in the presence of borane tetrahydrofuran. 2-methyl-CBS-oxazole boridine is widely used due to its relatively good stability in air and moisture. |
Last Update：2024-04-10 22:29:15
