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Advancement in Cascade [1,n]-Hydrogen Transfer/Cyclization: A Method for Direct Functionalization of Inactive C(sp3)[BOND]H Bonds

Authors

  • Liang Wang,

    1. College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, People's Republic of China
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  • Jian Xiao

    Corresponding author
    1. College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, People's Republic of China
    • College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, People's Republic of China

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Abstract

The cascade [1,n]-hydrogen transfer/cyclization, recognized one century ago, has received considerable interest in recent decades and great achievements have been made. This cascade process can functionalize C(sp3)[BOND]H bonds directly into C[BOND]C, C[BOND]N, C[BOND]O bonds under the catalysis by Lewis acids, Brønsted acids or organocatalysts, and even under thermal conditions. This methodology has shown preeminent power to construct 5- or 6-membered heterocyclic as well as all-carbon rings. In this review, various hydrogen donors and hydrogen acceptors are categorized and discussed.

Abbreviations: Cbz: benzyloxycarbonyl; Cod: 1,5-cyclooctadiene; CSA: camphorsulfonic acid; DCE: 1,1-dichloroethane; DFT: density function theory; DMF: N,N-dimethylformamide; DNBS: 2,4-dinitrobenzenesulfonic acid; DPP: diphenyl phosphate; ERC: electrocyclic ring closure; Fmoc: 9-fluorenylmethoxycarbonyl; HT: hydrogen transfer; IBX: ortho-iodoxybenzoic acid; m-CPBA: meta-chloroperbenzoic acid; MW: microwave; MS: molecular sieves; Pg: protecting group; p-TSA: para-toluenesulfonic acid; r.t.: room temperature; TCE: 1,1,2-trichloroethane; TFA: trifluoroacetic acid; TMS: trimethylsilyl.

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