Low-Valent Titanium-Mediated Radical Conjugate Addition Using Benzyl Alcohols as Benzyl Radical Sources

• DOI: 10.1021/acs.orglett.8b02305
• Publication Date: 2018-08-27T15:14:52Z
• Authors: Takuya Suga; Shoma Shimazu; Yutaka Ukaji
• Keywords: 01 natural sciences; 0104 chemical sciences

A concise method to directly generate benzyl radicals from benzyl alcohol derivatives has been developed. The simple and inexpensive combination of TiCl4(collidine) (collidine = 2,4,6-collidine) and manganese powder afforded a low-valent titanium reagent, which facilitated homolytic cleavage of benzylic C-OH bonds. The application to radical conjugate addition reactions demonstrated the broad scope of this method. The reaction of various benzyl alcohol derivatives with electron-deficient alkenes furnished the corresponding radical adducts.