Highly Diastereoselective Addition of Methyllithium to Chiral α,β-Dialkoxy Ketones and Its Application to the Stereocontrolled Asymmetric Synthesis of Highly Substituted Tetrahydrofurans
The nucleophilic addition of methyllithium to chiral α,β-dialkoxy 1,3-dithian-2-yl ketones in ether gave the corresponding Cram type of anti isomers in excellent diastereoselectivity. The method was applied to the stereocontrolled synthesis of optically active and highly substitutedtetrahydrofurans.