Asymmetric Synthesis of 3,3′-Tetrahydrofuryl Spirooxindoles via Palladium-Catalyzed [3+2] Cycloadditions of Methyleneindolinones with Vinylethylene Carbonates

Abstract

A palladium-catalyzed asymmetric [3+2] cycloaddition reaction of methyleneindolinones with vinylethylene carbonates has been successfully developed, which provides a highly efficient method for the synthesis of structurally diverse 3,3′-tetrahydrofuryl spirooxindoles in high yields (≤99%) with excellent stereoselectivities (>20:1 dr, ≤99% ee). Furthermore, this methodology shows a wide substrate scope and high utility in diversity-oriented synthesis.

Advances in Palladium‐Catalyzed Decarboxylative Cycloadditions of Cyclic Carbonates, Carbamates and Lactones

“…This method enabled the effective synthesis of several furofuran lignans with stereodivergency from readily available starting materials (Scheme 24, eq 3). In 2020, palladium‐catalyzed asymmetric DCs of VECs with methyleneindolinones 26 was disclosed by Wang and Hu's group (Scheme 24, eq 4) [14a] . This reaction delivered the 3,3’‐tetrahydrofuryl spirooxindoles 27 in high yields and excellent stereoselectivities.…”

“… Palladium‐catalyzed asymmetric decarboxylative [3+2] cycloadditions of VECs with electron‐deficient alkenes [10e–g,14a–d] …”

Research Progress of 1,3,5-Triazinanes in the Synthesis of Nitrogen-Containing Heterocycles

“…次年, 杨伟波课题组 [31] 在前期工作基础上, 通过分 步操作合成了四氢嘧啶骨架 47 (Scheme 18). 首先钯催 化剂对碳酸乙烯酯 45 作用 2 h, 除去二氯甲烷后, 向反 应体系内加入甲醇和水的混合溶剂以及 1,3,5-三嗪烷, 继续反应 2 h. 与之前报道的碳酸乙烯酯作为三原 子 [32,33] 或者五原子 [34][35][36][37] 合成子的情况不同, 该机理研究 表明, 碳酸乙烯酯通过钯催化脱 CO 2 和 β-H 消除的组合 过程, 生成的 α,β-不饱和醛 46 作为三个碳合成子进行环 加成反应. 在合成四氢嘧啶骨架过程中, 三嗪烷提供 N-C-N 三原子合成子.…”

Chiral Bidentate Phosphoramidite-Pd Catalyzed Asymmetric Decarboxylative Dipolar Cycloaddition for Multistereogenic Tetrahydrofurans with Cyclic N-Sulfonyl Ketimine Moieties

“…Notably, vinylethylene carbonates (VECs) as a type of zwitterionic allylpalladium precursor are more stable and readily accessible than the traditional butadiene oxide and isoprene oxide . The zwitterionic allylpalladium intermediates from VECs can undergo the asymmertirc cycloaddition process with diverse substrates including aldehydes, imines, isothiocyanates, and methyleneindolinones alkenes with impressive outcomes. Just recently, Kim and co-workers reported Pd-catalyzed asymmetric [3 + 2] and [5 + 2] cycloadditions of sulfamate-derived cyclic imines and VECs in the presence of a phosphoramidite ligand or a diphosphine ligand, respectively (Scheme a) .…”

“…12 Notably, vinylethylene carbonates (VECs) as a type of zwitterionic allylpalladium precursor are more stable and readily accessible than the traditional butadiene oxide and isoprene oxide. 13 The zwitterionic allylpalladium intermediates from VECs can undergo the asymmertirc cycloaddition process with diverse substrates including aldehydes, 14 imines, 15 isothiocyanates, 16 and methyleneindolinones alkenes 17 We commenced the study by screening reaction parameters for Pd-catalyzed asymmetric cycloaddition of VECs 1a and (E)-3-styrylbenzo[d]isothiazole 1,1-dioxide 2a. The reactions were typically conducted using 5 mol % of Pd 2 (dba) 3 and 12 mol % of a chiral ligand as the catalyst, and the results were summarized in Table 1.…”