Scope and Limitations of Chiral B-[3,5-Bis(trifluoromethyl)phenyl]oxazaborolidine Catalyst for Use in the Mukaiyama Aldol Reaction
摘要:
A new chiral oxazaborolidine catalyst was prepared in situ from 3,5-bis(trifluoromethyl)phenylboron dichloride and N-(p-toluenesulfonyl)-(S)-tryptophan. This catalyst is much more active than Corey's original catalyst for the Mukaiyama aldol reaction of aldehydes with silyl enol ethers. The observed syn selectivities and re-face attack of silyl enol ethers on carbonyl carbon of aldehydes imply that the extended-transition state model is applicable.
作者:Teruaki Mukaiyama、Nobuharu Iwasawa、Rodney W. Stevens、Toru Haga
DOI:10.1016/s0040-4020(01)82423-6
日期:1984.1
A highly diastereoselective cross aldolreaction is developed using divalent tin enolates formed from stannous trifluoromethanesulfonate and carbonyl compounds. The reaction is extended to a highly enantioselective cross aldolreaction employing chiral diamines derivedfrom (S)-proline as ligands.
benign method is advantageous from a green chemical viewpoint with regard to yield, substrates variation, reagent availability, and simple procedures. This method was applied to a short step formal synthesis of (R)-muscone, a natural macrocyclic musk.
efficient cross aldol additions between different ketones and between ketones and aldehydes, in good to excellent yields with high syn-stereoselectivities. As an extension, direct Claisencondensation between methyl esters was also promoted by TiCl4/Bu3N with 0.05 equiv of TMSOTf co-catalyst.
的TiCl 4 /卜3 Ñ进行不同酮类之间和酮和醛,在良好的以高优异的产率之间高效交叉醛醇添加顺-stereoselectivities。此外,TiCl 4 / Bu 3 N与0.05当量的TMSOTf助催化剂还促进了甲酯之间的直接Claisen缩合反应。
STANNOUS TRIFLATE: A NEW ALDOL REACTION VIA DIVALENT TIN ENOLATES
作者:Teruaki Mukaiyama、Rodney. W. Stevens、Nobuharu Iwasawa
DOI:10.1246/cl.1982.353
日期:1982.3.5
Divalent tin enolates formed from stannous triflate and ketones react with carbonyl compounds under mild conditions to give the corresponding aldol products in good yields. In the case of cross-cou...
A mild method for the diastereoselectiveMukaiyamaaldolreaction is reported. By using a lowloading of the gallium(III) triflatecatalyst (down to 0.01 mol-%), the transformation proceeds efficiently to afford the corresponding β-hydroxy ketones in yields up to 92 %. To the best of our knowledge, this is the first report of a metal triflate acting as a safe, bench-stable, and slow-releasing source