Kondoh Azusa, Hirozane Takayuki, Terada Masahiro
Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
Department of Chemistry, Graduate School of Science, Tohoku University Aramaki, Aoba-ku, Sendai, 980-8578, Japan.
Chemistry. 2022 Jul 26;28(42):e202201240. doi: 10.1002/chem.202201240. Epub 2022 Jun 10.
The formal enantioselective umpolung addition of dialkyl phosphites to 2-azaaryl ketones was developed under Brønsted base catalysis. The reaction involves the enantioselective protonation of the transient α-oxygenated (2-azaaryl)methyl anion generated through the 1,2-addition of the anion of dialkyl phosphite to the 2-azaaryl ketone and the subsequent [1,2]-phospha-Brook rearrangement. A chiral bis(guanidino)iminophosphorane organosuperbase efficiently catalyzed the reaction to provide enantio-enriched phosphates in high yields with good to high enantioselectivities. This is a rare example of the catalytic enantioselective protonation of transient carbanions other than enolates, constructing a trisubstituted stereogenic center α to 2-azaarenes.
在布朗斯特碱催化下，实现了亚磷酸二烷基酯对2-氮杂芳基酮的形式对映选择性极性反转加成反应。该反应涉及通过亚磷酸二烷基酯的阴离子对2-氮杂芳基酮进行1,2-加成生成的瞬态α-氧代（2-氮杂芳基）甲基阴离子的对映选择性质子化，以及随后的[1,2]-磷-布鲁克重排。一种手性双（胍基）亚氨基磷烷有机超强碱有效地催化了该反应，以高收率和良好至高的对映选择性提供对映体富集的磷酸盐。这是除烯醇化物外瞬态碳负离子催化对映选择性质子化的罕见例子，在2-氮杂芳烃的α位构建了一个三取代的立体中心。
