已经证明了 α-硼烯胺和烯酰胺在氮杂环合成中的使用。硼烯胺可以很容易地获得相应的 α-卤代醛,这些醛经过区域选择性环化形成硼化噻唑。缩合/酰胺化序列将 α-硼醛转化为稳定的 α-硼烯酰胺,而不会伴随 C → N 迁移。我们还表明,钯催化的 α-硼烯酰胺环化导致合成通用的异吲哚酮。这些分子随后可用于访问多环支架。
A new class of stable molecules, alpha-boryl aldehydes, has been prepared from oxiranyl N-methyliminodiacetyl boronates by a 1,2-boryl migration with concomitant epoxide scission. A range of boryl imines, alkenes, alcohols, acids, enol ethers, enamides, and other functionalized boronic acid derivatives that are difficult or impossible to prepare using established protocols can be accessed from alpha-boryl aldehydes. The chemoselective transformations of these building blocks, including the facile synthesis of functionalized unnatural amino acids from silyloxy and amido vinyl boronates, attest to the potential of alpha-boryl aldehydes in chemical synthesis.
Access to Cyclic Amino Boronates via Rhodium-Catalyzed Functionalization of Alkyl MIDA Boronates
作者:Jeffrey D. St. Denis、C. Frank Lee、Andrei K. Yudin
DOI:10.1021/acs.orglett.5b02861
日期:2015.12.4
sulfamate esters derived from amphoteric α-boryl aldehydes. Depending on the substitution pattern of the boryl sulfamate ester, a diverse range of five- or six-membered ring heterocycles are accessible using this transformation. The highly chemoselective nature of the C–H functionalization reaction preserves the alkyl boronate functional group, which enables the synthesis of B–C–N and B–C–C–N motifs
Boroalkyl Group Migration Provides a Versatile Entry into α-Aminoboronic Acid Derivatives
作者:Zhi He、Adam Zajdlik、Jeffrey D. St. Denis、Naila Assem、Andrei K. Yudin
DOI:10.1021/ja304173d
日期:2012.6.20
exemplifying migration of boron-substituted carbon is described. We show that α-boroalkyl groups of transient boroalkyl acyl azide intermediates readily migrate from carbon to nitrogen. This process allows access to a new class of stable molecules, α-boryl isocyanates, from α-borylcarboxylic acid precursors. The methodology facilitates synthesis of a wide range of α-aminoboronic acid derivatives, including
Amine hemilability enables boron to mechanistically resemble either hydride or proton
作者:C. Frank Lee、Diego B. Diaz、Aleksandra Holownia、Sherif J. Kaldas、Sean K. Liew、Graham E. Garrett、Travis Dudding、Andrei K. Yudin
DOI:10.1038/s41557-018-0097-5
日期:2018.10
MIDA boryl group in boron transfer processes, and show that the hemilability of the nitrogen atom on the MIDA ligand enables boron to mechanistically resemble either a hydride or a proton. The first case involves a 1,2-boryl shift, in which boron migrates as a nucleophile in its tetracoordinate form. The second case involves a neighbouring atom-promoted 1,4-boryl shift, in which boron migrates as an electrophile