Ruthenium-Catalyzed Direct Dehydrogenative Cross-Coupling of Allyl Alcohols and Acrylates: Application to Total Synthesis of Hydroxy β-Sanshool, ZP-Amide I, and Chondrillin
作者:Dattatraya H. Dethe、Nagabhushana C B
DOI:10.1021/acs.orglett.0c00200
日期:2020.2.21
Ru-catalyzed oxidative coupling of allyl alcohols and activated olefins has been developed by C(allyl)-H activation of allyl alcohols providing efficient and direct access to synthetically useful α,β-unsaturated enone intermediates. Synthetic utility of this method was demonstrated by its application to synthesis of bioactive natural products such as Hydroxy-β-sanshool, ZP-amide I, Chondrillin, Plakorin
Synthesis of New 3-(-2-Alkenyl)-2-hydroxy-5-methoxy-<i>p</i>-benzoquinones via Claisen Rearrangement of Original 5-Methoxy-4-(2-propenyloxy)-<i>o</i>-benzoquinones
The Claisen rearrangement is extended to compounds containing the benzoquinone moiety, obtained by regioselective nucleophilic substitution on 4-(p-methoxyphenoxy)-5-methoxy-o-benzoquinone (1). In the most general case, 5-methoxy-4-(2-propenyloxy)-o-benzoquinones 3 rearrange quantitatively into (E)-3-(2-alkenyl-2-hydroxy-5-methoxy-p-benzoquinones 4. Furfuryl or (2-thienyl)methyl ethers isomerize to 3-(2-methyl-3-furyl)- and 3-(2-methyl-3-thienyl)-2-hydroxy-5-methoxy-p-benzoquinones. This new synthetic method provides an efficient route to new hydroxybenzoquinones closely related to natural compounds. Thus, dihydroardisiaquinone A is synthesized in 5 steps from p-methoxyphenol.
Stereoselective synthesis of a versatile intermediate for the total synthesis of mono- and bis-THF containing annonaceous acetogenins
作者:Shyi-Tai Jan、Keqiang Li、Shikha Vig、Alexander Rudolph、Fatih M. Uckun
DOI:10.1016/s0040-4039(98)02222-9
日期:1999.1
stereogenic centers in 1 were established by Sharpless asymmetric epoxidation and Sharpless asymmetric dihydroxylation. Formation of the THF-ring unit was accomplished by acid catalyzed epoxide ring opening and 5-exocyclization reaction.
A general approach to γ-lactones via osmium-catalyzed asymmetric dihydroxylation. Synthesis of (−)- and (+)-muricatacin.
作者:Zhi-Min Wang、Xiu-Lian Zhang、K.Barry Sharpless、Subhash C. Sinha、Anjana Sinha-Bagchi、Ehud Keinan
DOI:10.1016/s0040-4039(00)79001-0
日期:1992.10
γ-lactones have been prepared highly enantioselectively (92–99% ee) using either AD-mix-β or AD-mix-α with both β,γ- and γ,δ-unsaturated esters. The method is exemplified by the three-step synthesis of (−) and (+)-muricatacin in 74% yield and >99% ee.
A convergent synthesis of two possible diastereomers of reticulatain-1 (1a and 1b) was accomplished. Comparison of the specific optical rotations of 1a and 1b did not allow for the strict determination of the absolute configuration. However, bis-(R)-MTPA esters of 1a and 1b showed a clear difference in chemical shifts in the 1H NMR spectra. If the bis-(R)-MTPA ester of natural reticulatain-1 (1) is
聚合合成了两种可能的reticulatain-1(1a和1b)非对映异构体。1a和1b的特定旋光度的比较不允许严格确定绝对配置。但是,1a和1b的双-(R)-MTPA酯在1 H NMR光谱中显示出明显的化学位移差异。如果天然网状甜菜碱-1(1)的bis-(R)-MTPA酯可用,则绝对构型为1将确定。用牛心脏线粒体复合物I检测了这些化合物的抑制作用。两种化合物显示出几乎相同的活性。