The first Mukaiyama reaction (1973)
In 1973 Mukaiyama, Narasaka and Banno reported that 1-(trimethylsilyloxy)cyclohexene, the silyl enol ether of cyclohexanone, reacts with benzaldehyde at −78 °C in the presence of TiCl4 and, after hydrolysis, gives 2-[hydroxy(phenyl)methyl]cyclohexanone in good yield.
It was the first time that a clean crossed aldol addition between a ketone and an aldehyde had been achieved without first forming a metal enolate: the silyl enol ether can be isolated and purified, and does not equilibrate with other regioisomers. The product is obtained as a mixture of the syn and anti diastereomers.