Radical Cascade-Triggered Controlled Ring-Opening Polymerization of Macrocyclic Monomers
作者:Hanchu Huang、Bohan Sun、Yingzi Huang、Jia Niu
DOI:10.1021/jacs.8b05365
日期:2018.8.22
strategy for the controlled radical ring-opening polymerization of macrocyclic monomers is reported. Key to this approach is an allyl alkylsulfone-based ring-opening trigger that can undergo a radical cascade reaction to extrude sulfur dioxide and generate an alkyl radical for controlled chain propagation. A systematic study correlating reaction conditions with polymer molecular weight and molecular
and enantioselectivity in the palladium‐catalyzed asymmetric allylic amination of racemic Morita–Baylis–Hillman adducts with aromatic amines. The methodology provides a facile and efficient synthesis of precursors for opticallyactiveβ‐lactam derivatives, including the cholesterol drug Ezetimibe.
The preparation of N-containing α,β-unsaturated carboxylate derivatives from α-silylamine and Baylis-Hillmanadducts under visible light irradiation was reported. The formation of α-aminoalkyl radical is regioselective compared with the previous reports. The reaction was successfully performed without additional additives under mild conditions.
The organocatalyzed regioselective allylic trifluoromethylation of Morita–Baylis–Hillman adducts using Ruppert–Prakash reagent was achieved in high to excellent yields via a successive SN2′/SN2′ mode for the first time. The reaction was extended to the asymmetric allylic trifluoromethylation by the use of a bis-cinchona alkaloid catalyst with high enantioselectivities up to 94% ee.
首次通过连续的S N 2'/ S N 2'模式,使用Ruppert-Prakash试剂对Morita-Baylis-Hillman加合物进行了有机催化的区域选择性烯丙基三氟甲基化反应,收率很高。通过使用具有高达94%ee的高对映选择性的双金鸡纳生物碱催化剂,反应扩展到不对称的烯丙基三氟甲基化反应。
Synthesis of multi‐functionalized carbonyl compounds by palladium–catalysed γ‐substitution of MBH adducts with activated amides
Catalytic allylic γ‐substitution with Morita‐Baylis‐Hillman (MBH) adducts for creating a new family of unsymmetrical dicarbonyl compounds was presented in this work, in which a variety of allylated amide products were achieved in good yields and high regioselectivity with excellent linear‐to‐branched ratios. Especially, it was found that the Pd/HZNU‐Phos complex exhibited remarkably high activity (with