Alkynylboronates are employed as a practical and versatile precursor for a variety of π-conjugated organic compounds. In the presence of a Cu(I) or Cu(II) salt, transformation of alkynylboronates into the corresponding 1,3-diynes upon exposure to air takes place readily in aprotic polar solvents such as DMI.
[3+2] Cycloaddition of Alkynyl Boronates and <i>in situ</i> Generated Azomethine Ylide
作者:Oleksandr S. Liashuk、Ihor A. Ryzhov、Oleksandr V. Hryshchuk、Yulian M. Volovenko、Oleksandr O. Grygorenko
DOI:10.1002/chem.202303504
日期:2024.2.21
[3+2] cycloaddition of alkynyl boronates and in situ generated azomethineylide is used for the selective scalable synthesis of pyrroline- and diazabicyclo[3.3.0]octane-derived boronates (i. e., 1 : 1 and 1 : 2 cycloadducts). The C−C and C−heteroatom bond-forming reactions of the obtained building blocks illustrate their utility for organic synthesis and drug discovery.
We have developed a synthesis of new allylboration reagents based on an allylic rearrangement. This approach led to the α-substituted γ-alkoxyallylboronates 2 with a high stereoselectivity in favor of the E-isomer, independent of the organometallic used. We have also studied the reactivity of these reagents toward aldehydes, showing that the allylboration reaction occurs with an excellent diastereoselectivity