Chen Y, Jiang W, Li B, Fu G, Chen S, Zhu H. Reaction of an N/Al FLP-based aluminum hydride toward alkynes: deprotonated alumination versus hydroalumination with regioselective cis-addition character.
Dalton Trans 2019;
48:9152-9160. [PMID:
31147661 DOI:
10.1039/c9dt00903e]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions of an N/Al FLP-based aluminum dihydride (o-TMP-C6H4)AlH2 (1, TMP = N(CMe2CH2)2CH2) with several terminal and internal alkynes were studied. 1 reacted with HC[triple bond, length as m-dash]CR by deprotonated alumination to yield (o-TMP-C6H4)Al(C[triple bond, length as m-dash]CR)2 (R = Ph (2), 1-C4H3S (3)) and with HC[triple bond, length as m-dash]CPPh2 by deprotonated alumination followed by HC[triple bond, length as m-dash]CPPh2 C(sp)-H-activation addition to yield [o-(TMP)H-C6H4]Al(C[triple bond, length as m-dash]CPPh2)3 (4). Furthermore, 1 reacted with R1C[triple bond, length as m-dash]CR2 to produce mono-hydroalumination compounds (o-TMP-C6H4)AlH(CR1[double bond, length as m-dash]CHR2) (R1,R2 = Ph,Ph (5), Ph,Et (6) and SiHMeR',Ph (7, R' = N(SiMe2Ph)-2,6-iPr2C6H3), all as monomers, as well as {(o-TMP-C6H4)AlH[C(PPh2)[double bond, length as m-dash]CHPh]}2 (8), a dimer formed due to the intermolecular P/Al donor-acceptor interaction. Moreover, bis-hydroalumination compounds (o-TMP-C6H4)Al(CR1[double bond, length as m-dash]CHR2)2 (R1,R2 = SiHMe2,PPh2 (9) and SiHPh2,PPh2 (10)) were produced. Natural Bond Orbital (NBO) analysis was performed, which revealed the inequivalent charge distribution on the C[triple bond, length as m-dash]C carbon atoms of the alkynes that have two different substituents. The electronic matching interaction between the Al-H and C[triple bond, length as m-dash]C bonds is discussed. The hydroalumination reaction exhibits the regioselective cis-addition character.
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