Synthesis of 1,3-dioxolanes by the addition of ketones to epoxides by using [Cp*Ir(NCMe)3]2+ as catalyst

A series of 1,3-dioxolanes have been prepared by the addition of ketones to epoxides in the presence of the catalyst [Cp*Ir(NCMe)(3)](2+), Cp*=C5Me5. The reactions proceed readily at 22 degrees C and the yields are good. The following 1,3-dioxolanes: 2,2,4-trimethyl-1,3-dioxolane, 1; 2,2-dimethyl-4-vinyl-1,3-dioxolane, 2; 2,2-dimethyl-4-phenyl-1,3-dioxolane, 3; 2,2-diethyl-4-methyl-1,3-dioxolane, 4; 2,2-diethyl-4-vinyl-1,3-dioxolane, 5; 2,2-diethyl-4-phenyl-1,3-dioxolane. 6 were prepared from the appropriate epoxide and carbonyl compounds. An inversion of configuration at the carbon atom at the C-O bond cleavage site of the epoxide was observed to occur in the formation of the dioxolanes: (R,S)- 2,2,4,5-tetramethyl-1,3-dioxolane, 7 and a mixture of (R,R)- and (S,S)-2,2,4,5-tetramethyl-1,3-dioxolane, 8 obtained from the reactions of acetone with (R,R)-/(S,S)-buten-2-oxide and R, S,-buten-2-oxide, respectively. (C) 1999 Elsevier Science S.A. All rights reserved.