Exploring Possible Surrogates for Kobayashi’s Aryne Precursors

Abstract

A class of aryne precursors, that is, 2-(trimethylsilyl)aryl 4-chlorobenzenesulfonates, has been developed through well-established synthetic routes, which allow the formation of arynes under relatively mild conditions. All the aryne precursors were obtained from phenols and 4-chlorobenzenesulfonyl chloride, an inexpensive and easy-to-handle reagent with relatively low toxicity, and subjected to nucleophilic addition reactions, providing addition products in yields of 24 to 92%, and to cycloaddition reactions, affording cycloadducts in yields up to 80%. This work provides interesting insights into the mechanisms of aryne generation. In addition, 2-(trimethylsilyl)phenyl 4-chlorobenzenesulfonate was successfully employed in the total synthesis of (±)-aporphine.

Atom Transfer Radical Polymerization-Inspired Room Temperature (sp3)C–N Coupling

“…HRMS m/z 210.1023 [M + H] + (calcd for C 13 H 12 N 3 , 210.1031). Data are consistent with those reported in the literature …”

“…1 H NMR (400 MHz, CDCl 3 ) δ/ppm 7.99 (d, J = 8.2 Hz, 1H), 7.61− 6.95 (m, 8H), 5.76 (s, 2H). 13 29 Larger-Scale (10 mmol) Preparation of 1-Benzyl-1H-benzo-[1,2,3]triazole 3. To a flask containing copper(I) bromide (71 mg, 0.50 mmol), potassium tert-butoxide (1.23 g, 11 mmol), and benzotriazole (1.20 g, 10 mmol) under dry N 2 were added toluene (12 mL) and then PMDETA (0.15 mL, 0.75 mmol).…”

Biobased C6-Furans in Organic Synthesis and Industry: Cycloaddition Chemistry as a Key Approach to Aromatic Building Blocks

“…A broad scope of benzoannulated 7-oxanorbornenes can be obtained via this approach. The utilization of diarynes (Table ) and polycyclic arynes (Table ) leads to the formation of condensed polycyclic systems. …”

o-Silylaryl Triflates: A Journey of Kobayashi Aryne Precursors

“…Since 2000, many new generation protocols have been discovered. In 2002, Uchiyama et al demonstrated that lithium dialkyl­(2,2,6,6-tetramethylpiperidino)­zincate (R 2 Zn­(TMP)­Li) could efficiently activate halobenzenes. , In 2004, Knochel and co-workers revealed that o -iodoaryl sulfonates were able to serve as versatile aryne precursors by using isopropylmagnesium chloride ( i -PrMgCl) as the activating reagent. − Notably, aryne precursors bearing silyl groups as accepting groups (AGs) were developed by the groups of Kitamura (2006), Akai (2011), Novák (2012), Xu/Jiang/Wang (2015), Daugulis (2016), and Raminelli (2020), all of which were found to facilely generate benzyne under fluoride-induced conditions. Meanwhile, precursors containing OTf group as the LG were realized by Hosoya, where the AGs could be boronic ester (2013), arylsulfoxide (2014), and diarylphosphinyl groups (2018) .…”