An attempted conjugate addition of an allyl cuprate to the enone 10 failed and provided exclusively the corresponding 1,2-addition product. Therefore, a Hosomi-Sakurai reaction with allyltrimethylsilane was investigated. A screening of various Lewis acids, including titanium tetrachloride, 10 boron trifluoride diethyl etherate, iron(III) chloride, iodine, and indium, revealed indium(III) chloride in the presence of trimethylsilyl chloride to be the best system. Under these conditions, the 1,4-addition product 11 was isolated in 58% yield as a mixture of two diastereomers (dr 1:2.4) (Scheme 3). During the reaction, partial trapping of the enolate with trimethylsilyl chloride was observed. When triethylamine was added after completion of the conjugate addition, silyl enol ether 12 was obtained exclusively in 63% yield as a mixture of two diastereomers (dr 1:2) (Scheme 3). The configuration was determined three steps later by X-ray crystallographic analysis of intermediate 4. Unfortunately, the desired product turned out to be the minor diastereomer. Attempts to reverse the stereoselectivity were unsuccessful.