High-valent tin(IV) porphyrins: Efficient and selective catalysts for cyclopropanation of styrene derivatives with EDA under mild conditions

An efficient and selective method for cyclopropanation of styrene derivatives with ethyl diazoacetate (EDA) catalyzed by tin(IV) tetraphenylporphyrinato trifluoromethanesulfonate, [SnIV(TPP)(OTf)2], and tin(IV)tetraphenylporphyrinato tetrafluoroborate, [SnIV(TPP)(BF4)2] is reported. These electron-deficient catalysts catalyzed the cyclopropanation of styrene derivatives in high yields and short reaction times under mild conditions. The reactions were highly selective and only trans-isomers were produced. Electron-rich styrenes were reacted faster than electron-poor ones. The catalysts were reused several times without loss of their catalytic activity and diastereoselectivity.