764-35-2Relevant articles and documents
ON THE REACTION OF METALLATED ACETYLENES AND ALLENES WITH CARBON DISULFIDE. INFLUENCE OF THE ALKALI METAL COUNTER-ION AND THE SUBSTITUENTS IN THE ACETYLENE AND ALLENE ON THE COURSE OF THE REACTION
Jong, R. L. P. De,Brandsma, L.
, p. 277 - 282 (1986)
Addition at low temperatures of carbon disulfide to a solution of the lithium compound (R1 = CH3, C3H7, Ph, OCH3, SCH3) results in the initial formation of an allenic carbodithioate H2C=C=C(R1)CSSLi, while for R1 = t-C4H9 or SiMe3 acetylenic carbodithioates R1CCCH2CSSLi are formed.The initial products undergo very rapid subsequent reactions.For R1 = CH3 or C3H7 the lithium compound adds (in the allenic form) in a conjugated fashion to the C=C-C=S system of the allenic carbodithioate.The acetylenic dithioates are deprotonated to give the geminal dithiolates R1CC-CH=C(SLi)2.For R1 = Ph, OCH3 or SCH3, subsequent deprotonation at the terminal carbon atom of the initial allenic dithioate gives enyne dithiolates HCC-C(R1)=C(SCH3)2; this reaction proceeds more satisfactorily with the potassium compounds.
Polylithiumorganic compounds. Part 28. The reaction of allene and alkyl substituted allenes with lithium metal
Maercker, Adalbert,Tatai, Andrea,Grebe, Burkhard,Girreser, Ulrich
, p. 1 - 8 (2007/10/03)
The reaction of allene (3a) and alkyl substituted allenes 1,2-hexadiene (3b), cyclopropylallene (3c), and vinylidene cyclopropane (3d) with lithium metal was investigated in order to access 2,3-dilithioalkenes 4a-d. These dilithioalkenes 4a-d are very reactive in polar solvents like THF and act as strong bases, either metalation of the starting allene 3a-d, the solvent, or sufficiently acidic intermediates like 8 a-d is observed. The metalation products 5-7 show follow-up reactions like 1,3-H shift to the corresponding 1-lithio-1-alkynes 8 and subsequent metalation to the dilithioalkynes 9. Additionally, lithium hydride elimination and ring-chain rearrangement (for 5c) are observed. 1,2-Hexadiene (3b) can be brought to reaction with lithium metal in the apolar solvent pentane, here the follow-up reactions are much slower due to the insolubility of 4b. In all cases the elucidation of the reaction pathways is hampered by the formation of complex mixtures of, amongst others, regio- and stereoisomeric products upon quenching with simple electrophiles.
Isomerization of terminal alkynes catalyzed by itterbium(II)-aromatic imine complexes
Makioka, Yoshikazu,Taniguchi, Yuki,Kitamura, Tsugio,Fujiwara, Yuzo,Saiki, Akira,Takaki, Ken
, p. 349 - 356 (2007/10/03)
Ytterbium-aromatic imine dianion complexes 2, which can easily be prepared from metallic ytterbium and aromatic imines 1, can act as effective catalysts for the isomerization of terminal alkynes 3 under mild conditions to afford internal alk-2-ynes 4 in good yields.In the reaction of 1-hexene 3a, 2-hexyne 3a, 2-hexyne 4a can be simply obtained by trap-to-trap distillation and the catalytic system can be reused for the isomerization of 3a without other treatments. - Keywords: lanthanoid-imine complex; terminal alkyne; isomerization; alk-2-yne
