Metal Triflate–Catalyzed Se-Se Bond Cleavage and the Selective Additions Under Mild Conditions

Metal triflate–catalyzed Se-Se bond cleavage would generate selenyl cations, which could add to activated C=C double bond selectively. The reaction conditions were mild and could be easily handled. The cleavage of Se-Se bond in this novel way under mild conditions might expand the view of organic synthesis and facilitate new synthetic strategies. Display full size Keywords: Alleneselectrophilic additionregioselectivityseleniumstereoselectivity ACKNOWLEDGMENTS This work was supported by the University Natural Scientific Foundation of Jiangsu Province (No. 09KJB150014), the 45th Postdoctoral Foundation of China (No. 20090451249), and the National Natural Scientific Foundation of China (Nos. 20633010 and 20773106). Notes a 0.24 mmol of 1a (20% excess), 0.2 mmol of PhSeSePh, and 1 mL of DCM were employed. The dosage of LA was 0.5 equiv in entry 1 and 0.2 equiv in entries 2 to 9. b LA = Lewis acid. c The reaction was monitored by TLC (eluent: petroleum ether). d Isolated yields based on PhSeSePh. Z/E ratio was calculated from 1H NMR spectrum. a 0.24 mmol of 1a (20% excess), 0.2 mmol of PhSeSePh, and 1 mL of solvent were employed. b The reaction was monitored by TLC (eluent: petroleum ether). c Isolated yields based on PhSeSePh. Z/E ratio was calculated from 1H NMR spectrum. a Isolated yields. The configuration of 2 was established by the NOESY spectrum studies as well as Ref. 2i, and the Z/E ratio was calculated from the 1H NMR spectrum. a Isolated yields. The configuration of 6 was established by the NOESY spectrum studies as well as Ref. 2 h, and the Z/E ratio was calculated from the 1H NMR spectrum. b Compound 7 was obtained (Fig. 1).