Highly Enantioselective Imine Cinnamylation with a Remarkable Diastereochemical Switch
摘要:
The first general method for the enantioselective cinnamylation of aldimines is reported. The method utilizes a simple chiral cinnamylsilane reagent and is characterized by experimental simplicity and extraordinarily high levels of enantioselectivity. Further, a remarkable and unprecedented diastereochemical reversal has been realized whereby either diastereomer may be accessed from the same trans-cinnamylsilane based upon a subtle change to the imine, thus obviating the usual requirement for both the trans- and cis-cinnamylsilanes.
Structure influence of chiral 1,1′-biscarboline-N,N′-dioxide on the enantioselective allylation of aldehydes with allyltrichlorosilanes
作者:Bing Bai、Hua-Jie Zhu、Wei Pan
DOI:10.1016/j.tet.2012.06.042
日期:2012.8
A series of new axially chiral 1,1′-biscarboline-N,N′-dioxide Lewis base organocatalysts were examined in the asymmetricallylation of aldehydes with allyltrichlorosilane. The chiral catalysts (R)-1a–e bearing ester groups in 3,3′ position provided good yields of the homoallyl alcohols with excellent enantioselectivities up to 99% for a broad substrate scope that covers aliphatic, aromatic, heteroaromatic
Chiral sulfoxides as activators of allyl trichlorosilanes in the stereoselective allylation of aldehydes
作者:Vincenzo De Sio、Antonio Massa、Arrigo Scettri
DOI:10.1039/c002988b
日期:——
Chiral aryl methyl sulfoxides proved to be efficient activators in the asymmetric allylation of aldehydes with allyl trichlorosilanes. High enantioselectivity was found in the case of electron-poor aldehydes. The high levels of diastereoselectivity and the detection of nonlinear effects have allowed the elucidation of some mechanistic aspects of the reaction.
Diastereoselective Addition of Prochiral Nucleophilic Alkenes to α-Chiral <i>N</i>-Sulfonyl Imines
作者:David A. Gutierrez、James Fettinger、K. N. Houk、Kaori Ando、Jared T. Shaw
DOI:10.1021/acs.orglett.1c04219
日期:2022.2.11
to chiral α-alkoxy N-tosyl imines is described. Alkene geometry is selectively transferred to the newly formed carbon–carbon bond, resulting in stereochemicalcontrol of C1, C2, and C3 of the resulting 2-alkoxy-3-N-tosyl-4-alkyl-5-hexene products. A computational analysis to elucidate the high selectivity is also presented. This methodology was employed in the synthesis of two naturally occurring isomers