Rhodium‐Catalyzed Remote C(sp
<sup>3</sup>
)−H Borylation of Silyl Enol Ethers
作者:Jie Li、Shuanglin Qu、Wanxiang Zhao
DOI:10.1002/anie.201913281
日期:2020.2.3
rhodium-catalyzed remote C(sp3 )-H borylation of silylenolethers (SEEs, E/Z mixtures) by alkene isomerization and hydroboration is reported. The reaction exhibits mild reaction conditions and excellent functional-group tolerance. This method is compatible with an array of SEEs, including linear and branched SEEs derivedfrom aldehydes and ketones, and provides direct access to a broad range of structurally
Rhodium-Catalyzed Dehydrogenative Borylation of Aliphatic Terminal Alkenes with Pinacolborane
作者:Masao Morimoto、Tomoya Miura、Masahiro Murakami
DOI:10.1002/anie.201506328
日期:2015.10.19
Aliphatic terminal alkenes react with pinacolborane at ambienttemperature to afford dehydrogenative borylation compounds as the major product when iPr‐Foxap is used as the ligand with cationic rhodium(I) in the presence of norbornene, which acts as the sacrificial hydrogen acceptor. The reaction is applied to the one‐pot syntheses of aldehydes and homoallylic alcohols from aliphatic terminal alkenes
Enantiospecific Synthesis of <i>ortho</i>-Substituted Benzylic Boronic Esters by a 1,2-Metalate Rearrangement/1,3-Borotropic Shift Sequence
作者:Stefan Aichhorn、Raphael Bigler、Eddie L. Myers、Varinder K. Aggarwal
DOI:10.1021/jacs.7b05880
日期:2017.7.19
ortho-substituted benzylic boronic esters with formal 1,1′-benzylidene insertion into the C–B bond. The reaction occurs by a SN2′ elimination and 1,2-metalate rearrangement of the N-activated boronate complex to afford a dearomatized intermediate, which undergoes a Lewis-acid catalyzed 1,3-borotropic shift to afford the boronic ester products in high yield and with excellent enantiospecificity. The use of
已经研究了苄胺和硼酸酯之间的偶联反应。邻-Lithiated苄胺与硼酸酯反应,并且一个Ñ -activator,得到邻位与正规1,1'-亚苄基取代的插入苄硼酸酯到C-B键。该反应通过S N 2'的消除和N活化的硼酸酯络合物的1,2-金属化物重排而得到脱芳香化的中间体,该中间体经过路易斯酸催化的1,3-硼向转变以得到硼酸酯产物。高收率和优异的对映体特异性。使用富含对映体的α-取代的苄胺得到相应的具有高ee的仲硼酸酯。
Ate Complexes of Secondary Boronic Esters as Chiral Organometallic-Type Nucleophiles for Asymmetric Synthesis
作者:Robin Larouche-Gauthier、Tim G. Elford、Varinder K. Aggarwal
DOI:10.1021/ja2077813
日期:2011.10.26
The addition of an aryllithium reagent to a secondary boronicester leads to an intermediate boron-ate complex that behaves as a chiral nucleophile, reacting with a broad range of electrophiles with inversion of stereochemistry. Depending on the electrophile, the C-B bond can be converted into C-I, C-Br, C-Cl, C-N, C-O, and C-C, all with very high levels of stereocontrol. This discovery now adds a
<i>ortho</i>
-Directing Chromium Arene Complexes as Efficient Mediators for Enantiospecific C(sp<sup>2</sup>
)-C(sp<sup>3</sup>
) Cross-Coupling Reactions
作者:Raphael Bigler、Varinder K. Aggarwal
DOI:10.1002/anie.201711816
日期:2018.1.22
ortho‐lithiation of chromium arene complexes followed by boronate formation and oxidation, occurs with complete ortho‐selectivity and enantiospecificity to give the coupling products in excellent yields and with high functional group tolerance. An intermediate chromium arene boronate complex was characterized by X‐ray, NMR, and IR experiments to elucidate the reaction mechanism.