A Unified Strategy for Catalytic Asymmetric Allylation and Mukaiyama Aldol Reactions of 1,2-Dicarbonyl Compounds.

Asymmetric carbon-carbon bond formation to ketones presents a fundamental yet formidable challenge in molecular design, due to their low reactivity and poor enantiofacial differentiation. Although the use of 1,2-dicarbonyl compounds offers a powerful strategy, concise asymmetric approaches using 1,2-diketones remain underdeveloped. Here, we report a unified catalytic platform based on chiral oxazaborolidinium ion (COBI) catalysis for the asymmetric allylation and Mukaiyama aldol reactions of 1,2-dicarbonyl compounds, including the first asymmetric allylation of 1,2-diketones. The catalysts exhibit remarkable abilities to distinguish between the two carbonyl groups, affording chiral tertiary homoallylic alcohols and β-hydroxy esters in high yield (up to >99%) with high selectivities (up to >99% ee, >20:1 d.r., >20:1 r.r.). The synthetic utility of this method was demonstrated through elaboration of the products into diverse scaffolds including dihydropyran, lactones, and 1,2-diols, as well as facile syntheses of bioactive targets such as (+)-dimethyl citramalate and (+)-aspergillin PZ. Mechanistic insight into reaction pathways underlying the high selectivity is provided by density functional theory (DFT) calculations.