An efficient methodology for the synthesis of sphingoid-type bases is reported. It involves the stereoselective addition of a racemic 3-alkoxy allenylzinc to enantiopure N-tert-butylsulfinyl imines and a cross-metathesis reaction as the key steps. It has been successfully applied to the syntheses of sphinganine and naturally occurring bioactive related compounds, among which the hydrolysis product
The high-yielding and highly efficient stereoselectivesynthesis of enantiopure anti,anti and syn,antiacetylenic2-amino-1,3-diolstereotriads from α-alkoxy-tert-butanesulfinylimines bearing a stereocenter α to the imino group is reported. The stereoselectivity of the reaction of these tert-butanesulfinyl (tBS)-imines with allenylzinc (±)-1 was found to be controlled only by the configuration of the
propargylic amines or ethers react with aldehydes to give regioselectively the corresponding anti-homopropargylic alcohols with a high level of diastereoselectivity. Such selectivity could be obtained independently of the nature of the heteroatom (amine or ethers) or the acetylenic substituents. Excellent selectivities can be reached regardless of the aldehydes used, remarkably also with vinylic or acetylenic
Dynamic Kinetic Resolution Processes Based on the Switchable Configurational Instability of Allenyl Copper Reagents
作者:Chayma Ben Maamer、Pierre C. Mpawenayo、Baptiste Lecachey、Nacira Alouane、Pierre Mangeney、Arie van der Lee、Jérôme Marrot、Samira Bouaouli、Maya Guillaumont、Rafâa Besbes、Hélène Gerard、Emmanuel Vrancken、Jean-Marc Campagne
DOI:10.1021/acs.orglett.1c02095
日期:2021.8.20
the configurational stability of allenyl copper reagents. A judicious choice of the reaction conditions allows efficient dynamickineticresolution processes and gives a one-pot access to homopropargylic alcohols or amines bearing up to four contiguous defined stereogeniccenters.
揭示了烯基铜试剂的构型不稳定性。一项实验研究强调了 Li +和反应温度在控制丙二烯基铜试剂构型稳定性方面的关键作用。反应条件的明智选择允许有效的动态动力学拆分过程,并提供一锅法获得带有多达四个连续定义的立体中心的高炔醇或胺。
Ruthenium-Catalyzed Intermolecular Coupling of Vinylic 1,2-Bisboronates with Alkynes: Stereoselective Access to Boryl-Substituted Homoallylic Alcohols
作者:Barry M. Trost、Guoting Zhang
DOI:10.1021/jacs.0c01755
日期:2020.4.22
The ruthenium catalytic addition of alkenes to alkynes has been demonstrated as a powerful synthetic tool to form diene motifs and widely applied in the synthesis of complex molecules. How-ever, except for the intramolecular coupling, trisubstituted alkenes are unsatisfactory coupling partners with alkynes, presumably due to the increased steric hindrance. Herein, we discovered that the substituted