Regioselective Trapping of Terminal Di-, Tri-, and Tetraynes with Benzyl Azide
摘要:
The reaction of benzyl azide with terminal di-, tri-, and tetraynes appended with a range of functional groups has been explored. Standard reaction conditions for BnN3 catalyzed by CuSO(4)(.)5H(2)O gave alkynyl, butadiynyl, and hexatriynyl triazoles in moderate to good yields. The reaction proceeds regioselectively as determined by the X-ray crystallographic analysis of three derivatives (1c, 1d, and 3c), and no evidence of multiple azide addition to the polyyne framework is observed.
Highly Efficient and Selective Synthesis of Conjugated Triynes and Higher Oligoynes of Biological and Materials Chemical Interest via Palladium-Catalyzed Alkynyl−Alkenyl Coupling
摘要:
Iteration of a Pd-catalyzed reaction of alkynyl- and oligoynylzincs with (E)-ICH-CHCI followed by metalation-termination with electrophiles(E) has provided a linear route to conjugated tri- and tetraynes, and Pd-catalyzed monoalkynylation of 1,1-dibromoenynes accompanied by dehydrobromination has provided a convergent route to conjugated tri-, tetra-, and pentaynes. Both display unprecedented high efficiency and selectivity.
Alkyne Migration in Alkylidene Carbenoid Species: A New Method of Polyyne Synthesis
作者:Sara Eisler、Navjot Chahal、Robert McDonald、Rik R. Tykwinski
DOI:10.1002/chem.200204584
日期:2003.6.6
conditions (hexane solution, -78 degrees C), and the seemingly high migratoryaptitude of the alkynyl moiety provides for efficient rearrangement. This, in turn, allows for multiple rearrangements in a single molecule, greatly facilitating the construction of highly unsaturated substrates. This procedure is exploited for the rapid synthesis of symmetrical and unsymmetrical 1,3,5-hexatriynes, extended polyynes
Highly Enantioselective Alkynylation of Trifluoropyruvate with Alkynylsilanes Catalyzed by the BINAP−Pd Complex: Access to α-Trifluoromethyl-Substituted Tertiary Alcohols
作者:Kohsuke Aikawa、Yu̅ta Hioki、Koichi Mikami
DOI:10.1021/ol102541s
日期:2010.12.17
A highlyenantioselective alkynylation catalyzed by the dicationic (S)-BINAP−Pd complex with a variety of alkynylsilanes and trifluoropyruvate is described. The catalytic reaction is applicable to highlyenantioselective addition of polyyne to trifluoropyruvate to construct α-trifluoromethyl-substituted tertiaryalcohols as enantiomerically enriched forms. The alkynyl products can be converted into
作者:Thanh Luu、Boris J. Medos、Erin R. Graham、Danielle M. Vallee、Robert McDonald、Michael J. Ferguson、Rik R. Tykwinski
DOI:10.1021/jo101870y
日期:2010.12.17
Terminal di-, tri-, tetra-, and pentaynes substituted with a variety of functional groups react with benzyl azide in the presence of CuSO4 center dot 5H(2)O and ascorbic acid to give derivatives of 4-ethynyl-, 4-butadiynyl-, 4-hexatriynyl-, and 4-octatetraynyl-,2,3-triazoles in moderate to good yields. These reactions appear to proceed regioselectively, and functionalization occurs exclusively at the terminal alkyne moiety. As well, no evidence of multiple azide additions to the polyyne framework is observed. X-ray crystallographic analysis of nine derivatives is used to document the regioselectivity of the reaction as well as outline structural characteristics of the 1,2,3-triazole products.