Silver‐Triggered Activity of a Heterogeneous Palladium Catalyst in Oxidative Carbonylation Reactions

Abstract A silver‐triggered heterogeneous Pd‐catalyzed oxidative carbonylation has been developed. This heterogeneous process exhibits high efficiency and good recyclability, and was utilized for the one‐pot construction of polycyclic compounds with multiple chiral centers. AgOTf was used to remove chloride ions in the heterogeneous catalyst Pd‐AmP‐CNC, thereby generating highly active PdII, which results in high efficiency of the heterogeneous catalytic system.


Table of Contents
General information S1 Preparation of Pd-AmP-CNC S2 Characterizations of Pd-AmP-CNC S3 Determination of Cl/Pd molar ratios in Pd-AmP-CNC S4 General procedure for the preparation of allene amide 1 S5-S7

Determination of Cl/Pd molar ratios in Pd-AmP-CNC
The Pd amounts in Pd-AmP-CNC were determined by inductively coupled plasma mass spectrometry (ICP-MS).
The Clamounts in Pd-AmP-CNC were determined by the Mohr titration method: 30 mL deionized water, 0.01 M AgNO 3 , 5% K 2 CrO 4 . The standard curve was determined by titration using 0.01 M NaCl solution.
The experiments for determination of Cl/Pd molar ratios in Pd-AmP-CNC were repeated for 5 times, and the Cl/Pd molar ratios value were the average values. The Cl/Pd molar ratios before and after treatment by AgOTf were determined to be 2.1/1 and 0.03/1, respectively.

Preparation of allene amide 1g
To a solution of allene amide 1f ( The organic layer was separated, and the aqueous layer was extracted with Et 2 O (2 × 30 mL). The combined organic layers were dried over Na 2 SO 4 , filtered, and concentrated in vacuo.

For the preparation of allene amide 1l, 1o and 1p, see below:
Using the general procedure as described in ref. [2]: For 1l, using 4-methylcyclohexan-1-one as the ketone in the step of S1→S2.
For 1o, using BocNHNs instead of BocNHTs in the step of S3→1.

Recycling experiments:
To a solution of Pd-AmP-CNC (5.75 mg, 0.0025 mmol), AgOTf (1.28 mg, 0.005 mmol) and BQ (59.4 mg,0.55 mmol) in CDCl 3 (2.5 mL) was added allene amide 1a (164 mg, 0.5 mmol). The tube was closed with a septum, evacuated and filled with carbon monoxide gas using a balloon. The procedure was repeated three times. The reaction was stirred at room temperature for 30 min and then centrifuged for 5 min at 5000 rpm. The catalyst was washed with CDCl 3 (2 × 2 mL) before being used in the next run or for characterizations, and the supernatant was combined for the determination of yield by NMR using anisole as the internal standard.  (65.4 mg, 0.2 mmol). The tube was closed with a septum, evacuated and filled with carbon monoxide gas using a balloon. The procedure was repeated three times. The reaction was stirred at room temperature for 5 min and then centrifuged for 5 min at 5000 rpm. The yield of 2a was determined to be 47% by NMR using anisole as the internal standard. The supernatant was transferred to another clean reaction tube, closed with a septum, evacuated and filled with carbon monoxide gas using a balloon.
The procedure was repeated three times and the mixture was stirred at room temperature for another 30 min. Analysis of the reaction mixture showed that the yield of 2a was unchanged (still 47% yield as determined by NMR).

Determination of intermolecular competition KIE
To a solution of Pd-AmP-CNC (

S27
As shown in the 1 H NMR spectrum in Figure S5, the combined yield of 2a and 2a-d 5 was 6% (0.12/2), and the yield of 2a was 5%, thus the yield of 2a-d 5 was 1%.
Therefore, the ratio of 2a and 2a-d 5 was determined as 5:1. Furthermore, the combined recovery of 1a and 1a-d 6 was 92% (1.83/2), so the reaction conversion was 8%. Finally, the isotope effect value calculated from the product ratio and conversion of the reaction is 5.4 according to Sih's equation. [4]
The procedure was repeated three times. The reaction was stirred at 0 o C. The yields were determined by 1 H NMR measurements using anisole as the internal standard (see Table S2 and S3, respectively). Due to the nature of the experiment, plots to determine the KIE were taken for 1a ( Figure S6). S28 Figure S6. Linear function fit for reaction rate of 1a.

Crystal structure determination of 4m
Single crystal X-ray diffraction data for suitable crystals of compounds 4m were collected using Cu Kα radiation on a Bruker D8 VENTURE diffractometer equipped with a PHOTON II CPAD detector. The datasets were reduced and absorption corrections applied using the Bruker APEX3 suite. The crystal structures were solved and refined by SHELXT and SHELXL respectively. [5] The crystal structures were refined using full-matrix least-squares based on F 2 , with all non-hydrogen atoms anisotropically defined. For both compounds, all non-hydrogen atoms were located in the initial structure solution. All hydrogen atom positions for 4m were placed by means of a riding model. A summary of the crystallographic data and refinement parameters are provided in Table S4. CCDC (1916248) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from