Direct, Mild, and General <i>n</i>-Bu<sub>4</sub>NBr-Catalyzed Aldehyde Allylsilylation with Allyl Chlorides
作者:Makeda A. Tekle-Smith、Kevin S. Williamson、Isaac F. Hughes、James L. Leighton
DOI:10.1021/acs.orglett.7b03193
日期:2017.11.3
A direct, mild, and general method for the enantioselective allylsilylation of aldehydes with allyl chlorides is reported. The reactions are effectively catalyzed by 5 mol % of n-Bu4NBr, and this rate acceleration allows the use of complex allyl donors in fragment-coupling reactions and of electron-deficient allyl donors. The results are (1) significant progress toward a “universal” asymmetric aldehyde
Bis(oxazolinyl)phenylrhodium(III) Aqua Complex: Efficiency in Enantioselective Addition of Methallyltributyltin to Aldehydes under Aerobic Conditions
作者:Yukihiro Motoyama、Hisao Nishiyama
DOI:10.1055/s-2003-41474
日期:——
A simple and general protocol is described for the enantioselective addition of methallyltributyltin to aldehydes catalyzed by chiral (Phebox)RhCl2(H2O) complexes 1 [Phebox = 2,6-bis(oxazolinyl)phenyl]. The reaction can be performed even under aerobic conditions to afford the corresponding optically active homoallylic alcohols in good yields with high enantioselectivities (90-99% ee).
Catalytic Asymmetric Allylation of Aldehydes and Related Reactions with Bis(((S)-binaphthoxy)(isopropoxy)titanium) Oxide as aμ-Oxo-Type Chiral Lewis Acid
ee. This asymmetric allylation with non-racemic bis-Ti(IV) oxide 3 and partially resolved (S)-BINOL shows a positive nonlinear effect in correlation of the enantiopurity of the allylation product with the ee of the (S)-BINOL. Chiral bis-Ti(IV) oxide (S,S)-3 can also be utilized for related reactions such as asymmetric methallylation and propargylation of aldehydes with high enantioselectivity. This asymmetric
Catalytic asymmetric methallylation and propargylation of aldehydes with bis(((S)-binaphthoxy)(isopropoxy)titanium) oxide
作者:Shunsuke Konishi、Hideo Hanawa、Keiji Maruoka
DOI:10.1016/s0957-4166(03)00247-7
日期:2003.6
New and highly efficient enantioselective methallylation and propargylation of achiral aldehydes with methallyltributyltin and allenyltributyltin, respectively, can be achieved with high enantioselectivity under the influence of chiral bis(((S)-binaphthoxy)(isopropoxy)titanium) oxide as catalyst.
Scope and Limitations of the Scandium-Catalyzed Enantioselective Addition of Chiral Allylboronates to Aldehydes
作者:Dennis G. Hall、Michel Gravel、Hugo Lachance、Xiaosong Lu
DOI:10.1055/s-2004-822359
日期:——
Scandium triflate catalyzes the addition of camphor-derived allyl-, methallyl-, and crotylboronates to aldehydes to provide homoallylic alcohols with excellent diastereo- and enantioselectivity. Aromatic, aliphatic, and propargylic aldehydes can be used successfully in this system. Additional advantages of the camphor-diol allylboronates are their ease of synthesis, their availability in both enantiomeric forms, and their stability towards silica gel chromatography. The usefulness of this methodology is further demonstrated by the gram-scale synthesis of various homoallylic alcohols of high enantiomeric excess and by the concise synthesis of the pheromone (4S)-2-methyloctan-4-ol.