77312-73-3Relevant articles and documents
Reductive cleavage of acetals and ketals with 9-borabicyclo[3.3.1]nonane
Soderquist, John A.,Kock, Iveliz,Estrella, Maria E.
supporting information, p. 1076 - 1079 (2012/12/23)
The reductive cleavage of benzaldehyde acetals and acetophenone ketals with the air-stable crystalline 9-borabicyclo[3.3.1]-nonane dimer provides monobenzylated ether derivatives of diols and 1,2-oxygen-transposed β-phenethyl alcohols, respectively. The boron moiety is effectively recovered through simple procedures which involve convenient air-stable reagents and boron byproducts. The process is particularly selective for 1,3-diols giving the more substituted monobenzyl ether derivatives exclusively. With acetophenone ketals both reduction and elimination occur, permitting 9-BBN-H to hydroborate the resulting styrene to produce 1,2-oxygen-transposed β-phenethyl alcohols cleanly. Potential applications of this new process were illustrated with the synthesis of the hallucinogen, mescaline, and the analgesic, ibufenac.
Hydrogenation of α-Keto Ethers: Dynamic Kinetic Resolution with a Heterogeneous Modified Catalyst and a Heterogeneous Base
Studer, Martin,Blaser, Hans-Ulrich,Burkhardt, Stephan
, p. 511 - 515 (2007/10/03)
The first successful example of the asymmetric hydrogenation of substituted α-keto ethers with Cinchona-modified Pt/Al2O3 is reported. In the absence of an additional base, kinetic resolution of the racemic starting material was observed with high diastereoselectivity and ee's up to 98% at conversions of a strong reaction acceleration but racemic product. Immobilization of OH- on solid ion exchangers resulted in the desired dynamic kinetic resolution, and ee's of >80% were obtained at >95% conversion. These effects are rationalized on the basis of a simple kinetic and structural model.
Methylaluminum bis(4-substituted-2,6-di-tert-butylphenoxide) as an efficient nonchelating Lewis acid: Application to asymmetric Diels-Alder reaction and diastereoselective alkylation to alkoxy carbonyl substrates
Maruoka, Keiji,Oishi, Masataka,Shiohara, Kei,Yamamoto, Hisashi
, p. 8983 - 8996 (2007/10/02)
The exceptionally bulky methylaluminum bis(4-substituted-2,6-di-tert-butylphenoxide) such as MAD or MABR can be successfully utilized as a highly efficient nonchelating Lewis acid for achieving high stereoselectivity in 1,n asymmetric induction in cyclic