P‐Stereogenic Secondary Iminophosphorane Ligands and Their Rhodium(I) Complexes: Taking Advantage of NH/PH Tautomerism

Abstract

Have a good SIP: P-stereogenic secondary iminophosphorane (SIP) ligands with a sulfonyl group attached to nitrogen have been prepared. In the presence of rhodium, the tautomeric equilibrium is shifted from the favored PH tautomer towards the P(III) tautomer, thereby allowing coordination of the SIP ligand through the P and O atoms. The resulting Rh complexes are effective in the [2+2+2] cycloaddition of enediynes with terminal alkynes.

Efficient Synthesis of Polycyclic γ‐Lactams by Catalytic Carbonylation of Ene‐Imines via Nickelacycle Intermediates

“…The chiral phosphoramidite ligand L*1 worked well to give 2 h in 95 % yield and 62 % ee . The chiral MOP ligand L*2 , P‐stereogenic iminophosphorane L*3 , and the planar‐chiral phosphine‐olefin ligand L*4 were also used, as these compounds should act as hemilabile bidentate ligands. However, any improvements on the results were not observed.…”

The Choice of Rhodium Catalysts in [2+2+2] Cycloaddition Reaction: A Personal Account

“…For a wide range of terminal and non-terminal diynes with different tethers (tosyl, malonates, oxygen, methylene-tethered) and with monoand disubstituted alkynes, excellent yields of the corresponding cycloadducts 71, in mild reaction conditions and with short reaction times, were obtained. Two years later, with the aim of improving the enantioselectivity in the cycloaddition of our enediyne systems, we tested a second type of chiral ligands designed by the same group in Barcelona [45]: P-stereogenic secondary iminophosphorane ligands (SIP). Secondary iminophosphoranes posses chirality at the phosphorous atom, and they present a PH/NH tautomeric equilibrium that preserves the chiral information.…”

Enantioselective Synthesis of P-Stereogenic Compounds

“…产物 46, 47 及 52 都可以转化为化合物 48, 它是首次被合成的氨基取代 的膦化物. 化合物 48 可进一步转化为 49, 在铑催化取 代烯烃的不对称氢化当中, 49 可作为手性配体能很好地 控制反应的立体选择性; 衍生物 50 也可用于铑催化的 分子内[2＋2＋2]环加成反应 [29] .…”