CC BY ND NC 4.0 · Synlett 2019; 30(04): 511-514
DOI: 10.1055/s-0037-1612230
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Photoinduced 1,2-Hydro(cyanomethylation) of Alkenes with a Cyanomethylphosphonium Ylide

,
Daisuke Moriyama
,
Yuuta Funakoshi
,
Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan   Email: tmiura@sbchem.kyoto-u.ac.jp   Email: murakami@sbchem.kyoto-u.ac.jp
› Author Affiliations
This work was supported by JSPS KAKENHI [Scientific Research (S) (15H05756) and (C) (16K05694)]
Further Information

Publication History

Received: 22 December 2018

Accepted after revision:23.01.2019

Publication Date:
13 February 2019 (eFirst)

 

Published as part of the 30 Years SYNLETT – Pearl Anniversary Issue

Abstract

An efficient method has been developed for the 1,2-hydro(cyanomethylation) of alkenes, in which a cyanomethyl radical species is generated from a cyanomethylphosphonium ylide by irradiation with visible light in the presence of an iridium complex, a thiol, and ascorbic acid. The cyanomethyl radical species then adds across the C=C double bond of an alkene to form an elongated alkyl radical species that accepts a hydrogen atom from the thiol to produce an elongated aliphatic nitrile. The ascorbic acid acts as the reductant to complete the catalytic cycle.

Supporting Information

 
  • References and Notes


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  • 17 6-Phenylhexanenitrile (3a); Typical Procedure A vial (2–5 mL; Biotage, Fisher Scientific) equipped with a stirrer bar was charged with the phosphorus ylide 2 (302 mg, 1.00 mmol), fac-Ir(ppy)3 (3.30 mg, 0.005 mmol, 1.0 mol%), ascorbic acid (882 mg, 5.00 mmol), and KHSO4 (207 mg, 1.52 mmol). The vial was then flushed with argon gas and quickly capped with a Teflon septum. 4-Phenylbut-1-ene (1a, 67.6 mg, 0.51 mmol), C6F5SH (20.0 mg, 0.100 mmol, 20 mol%), distilled CH3CN (2.5 mL), and H2O (2.5 mL; degassed with argon gas for 30 min) were added from a syringe, and the mixture was stirred vigorously for 40 h under blue LED lights (470 nm, 23 W) while the vial was cooled with a fan. The mixture was then diluted with brine (25 mL) and extracted with CH2Cl2 (3 × 25 mL). The organic phase was dried (Na2SO4), filtered, and concentrated under reduced pressure to give a residue that was purified by column chromatography [silica gel, hexane/EtOAc (9:1)] to give a colorless oil; yield: 70.7 mg (0.41 mmol, 80%). IR (ATR): 2936, 2245, 1454 cm–1. 1H NMR (400 MHz, CDCl3): δ = 1.45–1.53 (m, 2 H), 1.63–1.73 (m, 4 H), 2.33 (t, J = 7.2 Hz, 2 H), 2.63 (t, J = 7.6 Hz, 2 H), 7.16–7.21 (m, 3 H), 7.26–7.31 (m, 2 H). 13C NMR (100 MHz, CDCl3): δ = 17.1, 25.3, 28.3, 30.5, 35.5, 119.7, 125.8, 128.3, 141.9. HRMS (EI+): m/z [M]+ calcd for C12H15N: 173.1204; found: 173.1205.