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Abstract Cyclobutanes are prominent structural components in natural products and drug molecules. With the advent of strain‐release‐driven synthesis, ring‐opening reactions of bicyclo[1.1.0]butanes (BCBs) provide an attractive pathway to construct these three‐dimensional structures. However, the stereoselective difunctionalization of the central C−C σ‐bonds remains challenging. Reported herein is a covalent‐based organocatalytic strategy that exploits radical NHC catalysis to achieve diastereoselective acylfluoroalkylation of BCBs under mild conditions. The Breslow enolate acts as a single electron donor and provides an NHC‐bound ketyl radical with appropriate steric hindrance, which effectively distinguishes between the two faces of transient cyclobutyl radicals. This operationally simple method tolerates various fluoroalkyl reagents and common functional groups, providing a straightforward access to polysubstituted cyclobutanes (75 examples, up to >19 : 1 d.r.). The combined experimental and theoretical investigations of this organocatalytic system confirm the formation of the NHC‐derived radical and provide an understanding of how stereoselective radical‐radical coupling occurs.
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Asymmetric Synthesis of Propargylic and Allenic Silanes, Germanes, and Stannanes
Abstract Enantioenriched propargylic and allenic derivatives of silicon, germanium, and tin are versatile building blocks for stereoselective synthesis. Consequently, considerable efforts toward their efficient and selective synthesis have been made, both through classical approaches for chirality transfer and catalytic enantioselective strategies that employ the latest developments in transition metal catalysis, organocatalysis, and photoredox catalysis. In this review, we survey broadly applicable synthetic strategies and discuss the scope and mechanistic details for specific protocols that afford these compounds in a regio‐ and stereoselective manner.
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- Award ID(s):
- 2400082
- PAR ID:
- 10591603
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Chemistry – An Asian Journal
- ISSN:
- 1861-4728
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/asia.202500105
