Borylation of Propargylic Substrates by Bimetallic Catalysis. Synthesis of Allenyl, Propargylic, and Butadienyl Bpin Derivatives
摘要:
Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal S(N)2' pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.
Copper‐Mediated Dichotomic Borylation of Alkyne Carbonates: Stereoselective Access to (
<i>E</i>
)‐1,2‐Diborylated 1,3‐Dienes versus Traceless Monoborylation Affording α‐Hydroxyallenes
作者:Kun Guo、Arjan W. Kleij
DOI:10.1002/anie.202014310
日期:2021.2.23
A mild copper‐mediated protocol has been developed for borylation of alkynyl cyclic carbonates. Depending on the nature of the borylating reaction partner, either stereoselective diborylation of the propargylic surrogate takes place, providing convenient access to (E)‐1,2‐borylated 1,3‐dienes, or traceless monoborylation occurs, which leads to α‐hydroxyallenes as the principal product. The dichotomy