Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride

• Beatrice Lansbergen,
• Catherine S. Meister and
• Michael C. McLeod

Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36

• trichloride; dichloroalkenes; Friedel–Crafts alkylation; rearrangement; trifluoroalkanes; Introduction 1,1-Dichloro-1-alkenes are valuable synthetic intermediates and have been employed in Pd-mediated cross couplings of one or both chlorine atoms [1][2][3][4][5][6][7], carbonylation reactions [8], and C–H

• dichloroalkenes [18][19][20]. The preparation of 1,1-dichloro-1-alkenes from hydrazones [21] and from 2,2,2-trichloroethyl carbonates [22] has also been reported. Internal difluoroalkanes have been used to generate chloroalkene products using AlEt2Cl [23][24]. In this article we describe the AlCl3-mediated

• -dichloro-1-alkenone 6a in 23% yield, without cleavage of the methyl ether [26] (Scheme 1). A similar AlCl3-promoted conversion of vinylic trifluoromethyl groups to 1,1-dichloroalkenes has previously been reported [27][28]. Additionally, 1,1-dichloroalkenes have also been prepared by the elimination of HCl

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• methoxy groups, permitting a deviation in reaction outcome. We next subjected α-alkyl-substituted phenylallenes 2n–v to the standard reaction conditions, which resulted in mixtures of exclusively the Z-dichloroalkenes (Z-3) and chlorodienes 4 (Scheme 4). When the para-Br and para-Cl phenylallenes bearing