Synthesis of Secondary and Tertiary Alkyl Boronic Esters by <i>gem</i>
-Carboborylation: Carbonyl Compounds as Bis(electrophile) Equivalents
作者:Dunfa Shi、Lu Wang、Chungu Xia、Chao Liu
DOI:10.1002/anie.201804684
日期:2018.8.6
tertiary alkyl boronic esters. The addition of B2pin2 to a carbonyl compound generates α‐oxyl‐substituted alkyl boron species. Organolithium and Grignard reagents are then applied as C nucleophiles for the 1,2‐metalate rearrangement process. The organolithium reagents can also be generated by C−H lithiation or halogen/lithium exchange. The use of chiral ligands led to the generation of chiral alkyl boronic
C–O Functionalization of α-Oxyboronates: A Deoxygenative <i>gem</i>-Diborylation and <i>gem</i>-Silylborylation of Aldehydes and Ketones
作者:Lu Wang、Tao Zhang、Wei Sun、Zeyu He、Chungu Xia、Yu Lan、Chao Liu
DOI:10.1021/jacs.7b02518
日期:2017.4.12
the success of this transformation is the base-promoted C-O bond borylation or silylation of the generated α-oxyboronates. Experimental and theoretical studies exhibit that the C-O bond functionalization proceeds via an intramolecular five-membered transition-state (9-ts) boryl migration followed by a 1,2-metalate rearrangement with OBpin as a leavinggroup. The transformation occurs with an inversion
A new method has been developed for the sequential gem-thioborylation of readily available aldehydes via the cobalt-catalyzed diboration reaction. The N-heterocyclic carbene (NHC)–cobalt complex has been used as a catalyst for the diboration of aldehydes to generate α-oxyl boronic esters, which react with lithium thiolates to form a tetracoordinate boronate species, which undergoes 1,2-metalate rearrangement
Catalytic Diboration of Aldehydes via Insertion into the Copper−Boron Bond
作者:David S. Laitar、Emily Y. Tsui、Joseph P. Sadighi
DOI:10.1021/ja064019z
日期:2006.8.1
Mesitaldehyde reacts cleanly with (IPr)CuB(pin) [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene); pin = 2,3-dimethyl-2,3-butanediolate] to afford the product complex 1, the first well-defined product of carbonyl group insertion into a metal-boron bond. Analysis of 1 by NMR spectroscopy and single-crystal X-ray diffraction indicates the formation of a copper-carbon and a boron-oxygen bond. A copper(I) precatalyst supported by the less sterically demanding ligand ICy (1,3-dicyclohexylimidazol-2-ylidene) achieves the efficient 1,2-diboration of aryl-, heteroaryl-, and alkyl-substituted aldehydes at room temperature.
Facile Formation of β-Hydroxyboronate Esters by a Cu-Catalyzed Diboration/Matteson Homologation Sequence
作者:Cameron M. Moore、Casey R. Medina、Peter C. Cannamela、Melissa L. McIntosh、Carl J. Ferber、Andrew J. Roering、Timothy B. Clark
DOI:10.1021/ol502767m
日期:2014.12.5
The copper-catalyzed diboration of aldehydes was used in conjunction with the Matteson homologation, providing the efficient synthesis of beta-hydroxyboronate esters. The oxygen-bound boronate ester was found to play a key role in mediating the homologation reaction, which was compared to the a-hydroxyboronate ester (isolated hydrolysis product). The synthetic utility of the diboration/homologation sequence was demonstrated through the oxidation of one product to provide a 1,2-diol.