A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes
作者:Ding-Wei Ji、Yan-Cheng Hu、Hao Zheng、Chao-Yang Zhao、Qing-An Chen、Vy M. Dong
DOI:10.1039/c9sc01527b
日期:——
Through rational evaluation of ligands and promoters, the reactivity of a key Pd(ii) species towards transmetalation or β-H elimination is manipulated.
通过对配体和促进剂的理性评估,可以操控关键的Pd(II)物种对于金属转移或β-H消除的活性。
Aluminum chloride catalyzed stereo- and regiospecific allylsilylation of alkynes: a convenient route to silyldienes
作者:Seung Ho Yeon、Joon Soo Han、Eunkee Hong、Youngkyu Do、Il Nam Jung
DOI:10.1016/0022-328x(95)00323-i
日期:1995.9
Allyltrimethylsilane reacts with phenylalkynes in the presence of aluminum chloride catalyst under mild conditions to afford silylphenyldienes in moderate yield. In this allylsilylation reaction, the silyl group adds regioselectively to the terminal carbon and the allyl group to the inner carbon of the triple bond. The allylsilylation of phenylacetylene gives the allylsilylated product having the silyl and allyl groups in the cis-position, while diphenylacetylene gives the trans product. The allylic inversion was also observed in the allylsilylation with the stereohomogeneous (Z)-crotyltrimethylsilane. These results are consistent with the initial formation of trimethylsilyl cation intermediate and a stepwise process of allylsilylation.
“Design” of Boron-Based Compounds as Pro-Nucleophiles and Co-Catalysts for Indium(I)-Catalyzed Allyl Transfer to Various Csp3-Type Electrophiles
作者:Hai Thanh Dao、Uwe Schneider、Shū Kobayashi
DOI:10.1002/asia.201100096
日期:2011.9.5
our work highlights for the first time the correlation between the Lewis acidity of “electrophilic” boron‐based compounds and their “nucleophilic” reactivity in Csp3–Csp3 couplings, catalyzed by a “soft” low‐oxidation main group metal. In addition, we also report several applications of these methodologies to the selective synthesis of various carbohydrate derivatives.
Tetraphenylporphyrin-Catalyzed Tandem Photooxygenation of Polyenes and 1,4-Dienes: Multiple and Diverse Oxyfunctionalizations
作者:Axel G. Griesbeck、Alan de Kiff、Margarethe Kleczka
DOI:10.1002/adsc.201400565
日期:2014.9.15
Tandem singlet oxygen reactions photocatalyzed by meso‐tetraphenylporphyrin were performed with substrates designed for primary α‐gem‐selectivity or high vinylogous gem‐selectivity. The 1,3,5‐triene ester 1 was designed as a model compound for the natural compound crocin and resulted in a highly regioselective singlet oxygen ene reaction with ε‐hydrogen activation (93:7 ene vs. [4+2] cycloaddition)