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101.
N. V. Vorontsova V. I. Rozenberg E. V. Vorontsov O. L. Tok Yu. N. Bubnov 《Russian Chemical Bulletin》2000,49(5):912-919
Stereoselectivity of allylboration of 4-formyl[2.2]paracyclophane, 4-acetyl[2.2]paracyclophane, and 4-hydroxy-5-formyl[2.2]paracyclophane
was studied and the relative configurations of the homoallylic alcohols obtained were established. Optically pure (Sp,Sc)-(+)-4-(4-hydroxy-1-methylbut-3-enyl)[2.2]paracyclophane and (Rc,Sc)-(+)-4-hydroxy-5-(4-hydroxybut-3-enyl)[2.2]paracyclophane were synthesized. The possibility of using (Sp,Sc)-(+)-4-(4-hydroxy-4-methylbut-3-enyl)[2.2]paracyclophane as a recoverable chiral auxiliary in asymmetric allylboration of
aldehydes was demonstrated.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 914–921, May, 2000. 相似文献
102.
The reaction of triallylborane (All3B, 1) with various 1-alkynylsilanes of the type Me3Si–CCR1 [R1=H (2a), Me (2b), Ph (2c), CC–SiMe3 (2d), SiMe3 (2e)], Ph3Si–CCPh (3) MeCC–SiMe2SiMe2–CCMe (4) and Me2Si(Cl)–CCPh (5) was studied. Triallylborane 1 turned out to be much more reactive than other triorganoboranes R3B (e.g. R=Et, Ph). In the cases of 2 and 5, the products are organometallic-substituted alkenes 6 and 11, respectively, with the boryl and silyl group in cis-positions as the result of selective 1,1-allylboration (via cleavage of the Si–C bond) or mixtures of such and other alkenes 7 or 8 because of competition between 1,1- and 1,2-allylboration (the composition of these mixtures depends on the polarity of the solvent). In the case of 4, the 1,2-dihydro-1,2-disilaborepine derivative 12 is formed selectively (twofold 1,1-allylboration). The alkyne 3 did not react with 1. The products were characterised by 1H-, 11B-, 13C- and 29Si-NMR spectroscopy. 相似文献