Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
J Am Chem Soc. 2021 Jun 9;143(22):8255-8260. doi: 10.1021/jacs.1c04016. Epub 2021 May 24.
Alkynylphosphines are rarely used as ligands in asymmetric metal catalysis. We synthesized a series of chiral bis(oxazoline)alkynylphosphine ligands and used them in Rh-catalyzed highly regio- and enantioselective allylic amination reactions of 1,2-disubstituted allylic phosphates. Chiral 1,2-disubstituted allylic amines were synthesized in up to 95% yield with >20:1 branched/linear (b/l) ratio and 99% from racemic 1,2-disubstituted allylic precursors. The sterically smaller linear alkynyl group on the P atom in the bis(oxazoline)alkynylphosphine ligands was the key to fit the new requirements of the introduction of bulky 2-R' groups.
炔基膦配体在不对称金属催化中很少被使用。我们合成了一系列手性双（恶唑啉）炔基膦配体，并将其用于 Rh 催化的 1,2-二取代烯丙基磷酸酯的高区域和对映选择性烯丙基胺化反应。手性 1,2-二取代烯丙基胺以高达 95%的收率合成，具有>20:1 的支化/线性（b/l）比和 99%的对映选择性，来自外消旋 1,2-二取代烯丙基前体。在双（恶唑啉）炔基膦配体中 P 原子上的空间位阻较小的线性炔基基团是适应引入大体积 2-R'基团的新要求的关键。
