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We report herein catalytic asymmetric transformations of racemic α-borylmethyl-( E )-crotylboronate. The Brønsted acid-catalyzed kinetic resolution–allylboration reaction sequence of the racemic reagent gave ( Z )-δ-hydroxymethyl- anti -homoallylic alcohols with high Z -selectivities and enantioselectivities upon oxidative workup. In parallel, enantioconvergent pathways were utilized to synthesize chiral nonracemic 1,5-diols and α,β-unsaturated aldehydes with excellent optical purity.
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Stereochemical Control via Chirality Pairing: Stereodivergent Syntheses of Enantioenriched Homoallylic Alcohols
Abstract 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 gaveZ‐anti‐homoallylic alcohols with excellent enantioselectivities andZ‐selectivities. When the enantiomeric acid catalyst (R)‐Awas utilized, the stereoselectivity was completely reversed andE‐anti‐homoallylic alcohols were obtained with highE‐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.
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- PAR ID:
- 10307071
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 60
- Issue:
- 45
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 24096-24106
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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