(R)-2-Methyl-CBS-oxazaborolidine

{{DISPLAYTITLE:(R)-2-Methyl-CBS-oxazaborolidine}}

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 477343124

| Name =(R)-2-Methyl-CBS-oxazaborolidine

| ImageFile = (R)-2-Methyl-CBS-oxazaborolidine.svg

| PIN = (3aR)-1-Methyl-3,3-diphenyltetrahydro-1H,3H-pyrrolo[1,2-c][1,3,2]oxazaborole

| OtherNames = (R)-Methyl oxazaborolidine; (R)-(+)-2-methyl-CBS-oxazaborolidine

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 8014210

| PubChem = 9838490

| EC_number = 601-151-0

| InChIKey = VCDGSBJCRYTLNU-AZWGFFAPBY

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C18H20BNO/c1-19-20-14-8-13-17(20)18(21-19,15-9-4-2-5-10-15)16-11-6-3-7-12-16/h2-7,9-12,17H,8,13-14H2,1H3/t17-/m1/s1

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = VCDGSBJCRYTLNU-AZWGFFAPSA-N

| CASNo_Ref = {{cascite|changed|??}}

| CASNo = 112022-83-0

| SMILES = O2B(N1CCC[C@@H]1C2(c3ccccc3)c4ccccc4)C

| InChI = 1/C18H20BNO/c1-19-20-14-8-13-17(20)18(21-19,15-9-4-2-5-10-15)16-11-6-3-7-12-16/h2-7,9-12,17H,8,13-14H2,1H3/t17-/m1/s1

}}

|Section2={{Chembox Properties

| C=18 | H=20 | B=1 | N=1 | O=1

| Appearance = Colorless to pale yellow liquid (in toluene)

| Density = 0.95 g/mL

| MeltingPtC = 85 to 95

| MeltingPt_notes =

| BoilingPtC = 111

| BoilingPt_notes =

}}

|Section7={{Chembox Hazards

| GHSPictograms = {{GHS02}}{{GHS05}}{{GHS07}}{{GHS08}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|224|225|302|304|315|318|319|332|335|336|361|373}}

| PPhrases = {{P-phrases|201|202|210|233|240|241|242|243|260|261|264|270|271|280|281|301+310|301+312|302+352|303+361+353|304+312|304+340|305+351+338|308+313|310|312|314|321|330|331|332+313|337+313|362|370+378|403+233|403+235|405|501}}

}}

|Section8={{Chembox Related

| OtherAnions =

| OtherCations =

}}

}}

(R)-2-Methyl-CBS-oxazaborolidine is an organoboron catalyst that is used in organic synthesis. This catalyst, developed by Itsuno{{cite journal |author1=Hirao, A. |author2=Itsuno, S. |author3=Nakahama, S. |author4=Yamazaki, N. | journal = J. Chem. Soc. Chem. Commun. |title=Asymmetric reduction of aromatic ketones with chiral alkoxy-amineborane complexes | year = 1981 |issue=7 | pages = 315–317 |doi=10.1039/C39810000315}}{{cite journal |author1=Itsuno, S. |author2=Nakano, M. |author3=Miyazaki, K. |author4=Masuda, H. |author5=Ito, K. |author6=Hirao, A. |author7=Nakahama, S. | journal = J. Chem. Soc. Perkin Trans. 1 | year = 1985 | pages = 2039–2044 | doi = 10.1039/p19850002039 | title = Asymmetric synthesis using chirally modified borohydrides. Part 3. Enantioselective reduction of ketones and oxime ethers with reagents prepared from borane and chiral amino alcohols}} and Elias James Corey,{{cite journal |author1=Corey, E. J. |author2=Bakshi, R. K. |author3=Shibata, S. | journal = J. Am. Chem. Soc. | year = 1987 | volume = 109 | pages = 5551–5553 | doi = 10.1021/ja00252a056 | title = Highly enantioselective borane reduction of ketones catalyzed by chiral oxazaborolidines. Mechanism and synthetic implications | issue = 18|bibcode=1987JAChS.109.5551C }}{{cite journal |author1=Corey, E. J. |author2=Bakshi, R. K. |author3=Shibata, S. |author4=Chen, C.-P. |author5=Singh, V. K. | journal = J. Am. Chem. Soc.| year = 1987 | volume =109 | pages = 7925–7926 | doi = 10.1021/ja00259a075 | title = A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses | issue = 25|bibcode=1987JAChS.109.7925C }}{{cite journal |author1=Corey, E. J. |author2=Azimioara, M. |author3=Sarshar, S. | journal = Tetrahedron Lett. | year = 1992 | volume = 33 | pages = 3429–3430 | doi = 10.1016/S0040-4039(00)92654-6 | title = X-Ray crystal structure of a chiral oxazaborolidine catalyst for enantioselective carbonyl reduction | issue = 24|s2cid=97345807 }} is generated by heating (R)-(+)-2-(diphenylhydroxymethyl) pyrrolidine along with trimethylboroxine or methylboronic acid. It is an excellent tool for the synthesis of alcohols in high enantiomeric ratio. Generally, 2-10 mol% of this catalyst is used along with borane-tetrahydrofuran (THF), borane-dimethylsulfide, borane-N,N-diethylaniline, or diborane as the borane source. Enantioselective reduction using chiral oxazaborolidine catalysts has been used in the synthesis of commercial drugs such as ezetimibe and aprepitant.