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We report herein a rare example of enantiodivergent aldehyde addition with β‐alkenyl allylic boronates via chiral Brønsted acid catalysis. 2,6‐Di‐9‐anthracenyl‐substituted chiral phosphoric acid‐catalyzed asymmetric allylation using β‐vinyl substituted allylic boronate gave alcohols with R absolute configuration. The sense of asymmetric induction of the catalyst in these reactions is opposite to those in prior reports. Moreover, in the presence of the same acid catalyst, the reactions with β‐2‐propenyl substituted allylic boronate generated homoallylic alcohol products with S absolute configuration. Unusual substrate‐catalyst C−H⋅⋅⋅π interactions in the favoured reaction transition state were identified as the origins of observed enantiodivergence through DFT computational studies. [ABSTRACT FROM AUTHOR]

We report herein the development of stereodivergent syntheses of enantioenriched homoallylic alcohols using chiral nonracemic α‐CH2Bpin‐substituted crotylboronate. Chiral phosphoric acid (S)‐A‐catalyzed asymmetric allyl addition with the reagent gave Z‐anti‐homoallylic alcohols with excellent enantioselectivities and Z‐selectivities. When the enantiomeric acid catalyst (R)‐A was utilized, the stereoselectivity was completely reversed and E‐anti‐homoallylic alcohols were obtained with high E‐selectivities and excellent enantioselectivities. By pairing the chirality of the boron reagent with the catalyst, two complementary stereoisomers of chiral homoallylic alcohols can be obtained selectively from the same boron reagent. DFT computational studies were conducted to probe the origins of the observed stereoselectivity. These reactions generate highly enantioenriched homoallylic alcohol products that are valuable for rapid construction of polyketide structural frameworks. [ABSTRACT FROM AUTHOR]