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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(24):7093-7097
(E )‐δ‐Boryl‐substituted anti ‐homoallylic alcohols are synthesized in a highly diastereo‐ and enantioselective manner from 1,1‐di(boryl)alk‐3‐enes and aldehydes. Mechanistically, the reaction consists of 1) palladium‐catalyzed double‐bond transposition of the 1,1‐di(boryl)alk‐3‐enes to 1,1‐di(boryl)alk‐2‐enes, 2) chiral phosphoric acid catalyzed allylation of aldehydes, and 3) palladium‐catalyzed geometrical isomerization from the Z to E isomer. As a result, the configurations of two chiral centers and one double bond are all controlled with high selectivity in a single reaction vessel. 相似文献
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Tomoya Miura Naoki Oku Masahiro Murakami 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14762-14766
We report the highly diastereo‐ and enantioselective preparation of (E)‐δ‐boryl‐substituted anti‐homoallylic alcohols in two steps from terminal alkynes. This method consists of a cobalt(II)‐catalyzed 1,1‐diboration reaction of terminal alkynes with B2pin2 and a palladium(I)‐mediated asymmetric allylation reaction of the resulting 1,1‐di(boryl)alk‐1‐enes with aldehydes in the presence of a chiral phosphoric acid. Propyne, which is produced as the byproduct during petroleum refining, could be used as the starting material to construct homoallylic alcohols that are otherwise difficult to synthesize with high stereocontrol. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(38):11673-11677
An iridium‐catalyzed cyclocondensation of amino alcohols and aldehydes is reported. Intramolecular allylic substitution by an enamine intermediate and subsequent in situ reduction furnishes 3,4‐disubstituted piperidines with high enantiospecificity and good diastereoselectivity. The modular approach and the broad functional group tolerance provide access to diverse piperidine derivatives, which were further functionalized to give a versatile set of products. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(46):14899-14903
The individual molecules of α‐chloroalkenyl boronates include both an electrophilic C−Cl bond and a nucleophilic C−B bond, which makes them intriguing organic synthons. Reported herein is a stereodivergent synthesis of both E and Z α‐chloroalkenyl N ‐methyliminodiacetyl (MIDA) boronates through the direct chlorination of alkenyl MIDA boronates using t BuOCl and PhSeCl reagents, respectively. Both reaction processes are stereospecific and the use of sp3‐B MIDA boronate is the key contributor to the reactivity. The synthetic value of the boronate products was also demonstrated. 相似文献
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Brannon Sam Tom Luong Michael J. Krische 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(18):5555-5559
Ruthenium(II) complexes catalyze the C C coupling of 1,1‐disubstituted allenes and fluorinated alcohols to form homoallylic alcohols bearing all‐carbon quaternary centers with good to complete levels of diastereoselectivity. Whereas fluorinated alcohols are relatively abundant and tractable, the corresponding aldehydes are often not commercially available because of their instability. 相似文献