Construction of β to carbonyl stereogenic centres by asymmetric 1,4-addition of alkylzirconocenes to dienones and ynenones
作者:Zhenbo Gao、Stephen P. Fletcher
DOI:10.1039/c8cc01201f
日期:——
A new asymmetric addition of alkylzirconium species to dienones, a dienthioate, ynenones, and ynethionates with good yields and excellent ee's is reported.
of (E)-5-bromo-3-penten-2-one with triphenylphosphine affords a 3:1 mixture of two protomeric phosphoniumsalts 4-oxo 2 pentenyltriphenylphosphonium bromide and 4-oxo-1-pentenyltriphenyl-phosphonium bromide, characterized by the 13C NMR spectrum of the mixture. However, the common phosphorane of these salts gives two condensation products with benzaldehyde, corresponding to α- and γ-condensation respectively
(E)-5-溴-3-戊烯-2-酮与三苯基膦的反应,得到两种原始meric盐的3:1混合物:4-氧代2戊烯基三苯基溴化and和4-氧代-1-戊烯基三苯基-混合物的13 C NMR谱。但是,这些盐的常见磷烷会生成两个与苯甲醛的缩合产物,分别对应于α和γ缩合。
SHI, LILAN;XIA, WENJUAN;YANG, JIANHUA;WEN, XUEGING;HUANG, Y. Z., TETRAHEDRON LETT., 28,(1987) N 26, 2155-2158
作者:SHI, LILAN、XIA, WENJUAN、YANG, JIANHUA、WEN, XUEGING、HUANG, Y. Z.
DOI:——
日期:——
Ru-Catalyzed Chemo- and Enantioselective Hydrogenation of 2,4-Pentadien-1-ones: Synthesis of Chiral 2,4-Pentadien-1-ols
The asymmetrichydrogenation of 2,4-pentadien-1-ones has been achieved by using trans-RuCl2[(R)-XylylSunPhos][(R)-Daipen] as a catalyst under basic conditions. This hydrogenation demonstrated exclusive C1-carbonyl selectivity, and thus the conjugated 2,4-diene motifs remained untouched, which provides a synthetically useful method for various chiral 2,4-pentadien-1-ols.