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Formal Asymmetric Cycloaddition of Activated α,β-Unsaturated Ketones with α‑Diazomethylphosphonate Mediated by a Chiral Silver SPINOL Phosphate Catalyst

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journal contribution
posted on 2019-01-11, 19:19 authored by Bo Zheng, Haohua Chen, Lei Zhu, Xiqiang Hou, Yan Wang, Yu Lan, Yungui Peng
An efficient method for preparing highly functionalized chiral nonspiro-phosphonyl­pyrazolines via an asymmetric formal 1,3-dipolar cycloaddition reaction of α-diazomethyl­phosphonate with activated, acyclic α,β-unsaturated ketones, bearing an additional nitrile electron-withdrawing group, has been developed, utilizing an in situ generated chiral silver phosphate catalyst, affording excellent stereoselectivities (up to 98% ee, 99:1 dr) and yields (up to 95%). A stepwise mechanism is proposed based upon density functional M11 calculations.

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