ICl-Mediated Functional Group Interconversion from Methyl Homopropargyl Ether to α-Iodo-γ-chloroketone

Chen, Yu; Hee, Samual; Liu, Xiaochen; Das, Sajal; Hong, Dongsub; Leung, Pak‐Hing; Li, Yongxin; Li, Jiaming

doi:10.1021/acs.joc.2c01638

Cited by 1 publication

(2 citation statements)

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“…Herein, a known class of electrophilic-cyclization reactions − is mechanistically modified by intercepting the cyclized intermediates via nucleophilic ring opening with simultaneous group transfer, , in order to produce trisubstituted alkenes with regio- and stereochemical control. This ring-opening of the cyclized intermediate provides a mechanistic alternative to (i.e., “interruption of”) the well-established “Larock-type” pathway of electrophilic-cyclization dealkylation. − In previous work, the first example of this electrophilic-cyclization-group-transfer was demonstrated with boron as the electrophile, generating trisubstituted borylated alkenes with regio- and stereocontrol (Scheme a) . The term “group transfer” in this context refers to the transfer of the SAr group to a different carbon during the reaction.…”

Section: Introductionmentioning

confidence: 99%

“…However, generating regio-and stereodefined trisubstituted alkenes remains a significant synthetic challenge. 8−13 Herein, a known class of electrophilic-cyclization reactions 14−20 is mechanistically modified by intercepting the cyclized intermediates via nucleophilic ring opening with simultaneous group transfer, 21,22 in order to produce trisubstituted alkenes with regio-and stereochemical control. This ring-opening of the cyclized intermediate provides a mechanistic alternative to (i.e., "interruption of" 23 ) the wellestablished "Larock-type" pathway of electrophilic-cyclization dealkylation.…”

Section: ■ Introductionmentioning

confidence: 99%

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Iodination–Group-Transfer Reactions to Generate Trisubstituted Iodoalkenes with Regio- and Stereochemical Control

Kaplan,

Blum

2023

J. Org. Chem.

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The regio-and stereodefined synthesis of trisubstituted alkenes remains a significant synthetic challenge. Herein, a method is developed for producing regio-and stereodefined trisubstituted iodoalkenes by diverting intermediates from an iodination−electrophilic-cyclization mechanism. Specifically, cyclized sulfonium ion-pair intermediates are diverted to alkenes by ring-opening with nucleophilic iodide. Alternatively, scavenging of the iodide by AgOTf prevents ring-opening, enabling isolation of the sulfonium ion-pair intermediate. Isolation of the ion pair enables access to complementary reactivity, including ring-opening by alternative nucleophiles (i.e., amines), yielding trisubstituted acyclic alkenes and an example acyclic tetrasubstituted alkene. X-ray crystallographic determination of reaction intermediates and products confirms that the initial electrophilic-cyclization step sets the stereo-and regiochemistry of the product. The products serve as synthetic building blocks by readily participating in downstream functionalization reactions, including oxidation, palladium-catalyzed cross-coupling, and nucleophilic displacement.

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