Preparation and reactions of 4-iodobutyl pinacolborate. Synthesis of substituted alkyl and aryl pinacolboronates via 4-iodobutyl pinacolborate utilizing tetrahydrofuran as the leaving group
摘要:
Iodine reacts with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin), under ambient reaction conditions in THF, to form the iodoalkylborate species 2-(4-iodobutoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (4-IboxBpin). Apparently, one-half equivalent of 12 reacts with HBpin to form IBpin in pentanes, which in turn cleaves THF to form the 4-IboxBpin. Alkyl and aryl Grignard reagents, prepared under Barbier conditions, then react with 4-IboxBpin to form the corresponding alkyl and aryl pinacolboronates while reforming and liberating THF as the leaving group. Published by Elsevier Ltd.
An Opportunity for Mg-Catalyzed Grignard-Type Reactions: Direct Coupling of Benzylic Halides with Pinacolborane with 10 mol % of Magnesium
作者:Christine Pintaric、Sandra Olivero、Yves Gimbert、Pierre Y. Chavant、Elisabet Duñach
DOI:10.1021/ja1052973
日期:2010.9.1
Mg in catalytic amounts as the only metal permits the reductive coupling between benzyl halides and pinacolborane. HBpin acts both as an electrophile and as a reducing agent to regenerate an organomagnesium species in situ. An hydride oxidation mechanism is proposed on the basis of DFT calculations.
PROCESS FOR PREPARING BORONIC ACIDS AND ESTERS IN THE PRESENCE OF MAGNESIUM METAL
申请人:Dunach Isabel
公开号:US20110282090A1
公开(公告)日:2011-11-17
The present invention relates to the process for preparing a boronic acid or ester chemically, in which an aromatic compound is reacted with a boronating agent, in the presence of magnesium metal (Mg
0
). The invention also relates to the boronic acids or esters that can be obtained by means of this process and to the use thereof for example as a synthesis intermediate, in the Suzuki reaction, in the pharmaceutical or alternatively electronics field.
There is provided a series of coelenterazine (CTZ) derivatives as a substrate with high luminescence intensity, which is optimal for maximum luminescence wavelengths at both 400 nm (blue-shifted RLuc luminescence system) and 500 nm (ALuc luminescence system) for bioassays which is more sensitive than known techniques. The novel CTZ derivatives are compounds in which a specific position(s) of the CTZ is/are substituted with a specific substituent(s) as shown, for example, by the Formula [I],
and has a higher luminescence intensity than known CTZ derivatives in blue-shifted RLuc luminescence system or ALuc luminescence system.
<scp>Pd‐Catalyzed Site‐Selective</scp>
Borylation of Simple Arenes
<i>via</i>
Thianthrenation
<sup>†</sup>
作者:Xiao‐Yue Chen、Yu‐Hao Huang、Jian Zhou、Peng Wang
DOI:10.1002/cjoc.202000212
日期:2020.11
Site‐selective borylation of simple arenes was realized in one pot via an electrophilic thianthrenation/Pd‐catalyzed borylation sequence. The key to achieve this operatically simple process is the use of Pd catalysis, which could tolerate the solvent and acidic conditions used in the thianthrenation step. This protocol features mild conditions, broad functional group tolerance, and simple manipulations
Catalytic Boration of Alkyl Halides with Borane without Hydrodehalogenation Enabled by Titanium Catalyst
作者:Xianjin Wang、Penglei Cui、Chungu Xia、Lipeng Wu
DOI:10.1002/anie.202100569
日期:2021.5.25
titanium‐catalyzed boration of alkyl (pseudo)halides (alkyl‐X, X=I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition‐metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles,