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Conversion of Triple Bonds into Single Bonds in a Domino Carbopalladation with Norbornene
Author(s) -
Zhu Chuanle,
Chen Pengquan,
Zhu Rui,
Jiang Guangbin,
Lin Zhiming,
Wu Wanqing,
Jiang Huanfeng
Publication year - 2017
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201701241
Subject(s) - chemistry , triple bond , double bond , palladium , single bond , carbon fibers , ring (chemistry) , octane , stereochemistry , alkyl , organic chemistry , catalysis , materials science , composite number , composite material
A domino carbopalladation reaction of haloalkynes is presented. Remarkably, the four‐time carbopalladation process converts the carbon‐carbon triple bonds of haloalkynes stepwise into carbon–carbon double bonds, and finally to carbon‐carbon single bonds. Features of this reaction are that the carbon‐carbon double bonds of stable vinyl palladium intermediates are transformed into carbon‐carbon single bonds with the generation of unstable alkyl palladium intermediates. The subsequently formed π‐allylpalladium species are independently trapped by N ‐tosylhydrazones, boronic acids, and B 2 pin 2 in a highly diastereoselective manner, delivering the corresponding polycyclic and twisted products with a bicyclo[3.2.1]oct‐2‐en‐3‐yl)tricyclo[3.2.1.0 2,4 ]octane core skeleton in moderate to good yields via C−C and C−B bond formations. Significantly, the dual roles of norbornenes, ring construction and ring expansion, and the identification of electron‐rich tri(2‐furyl)phosphine as the ligand are found to be critical for the success of these transformations.