the total synthesis of murrayafoline-B and seven carbazole-1,4-quinone alkaloids. A palladium(II)-catalyzed oxidative cyclization is used to construct the carbazole skeleton. Pyran annulation and oxidation provide pyrayaquinone-A, -B, and -C. DIBAL-H-promoted reductiveringopening of pyrano[3,2-a]carbazole precursors leads to the prenylated and geranylated carbazole-1,4-quinone alkaloids murrayaquinone-B
献给教授迪特尔·恩德斯在他70之际个生日。 抽象的 我们描述了murrayafoline-B和七个咔唑-1,4-醌生物碱的总合成。钯(II)催化的氧化环化反应可用于构建咔唑骨架。吡喃环化和氧化提供吡喃醌-A,-B和-C。吡喃并[3,2- a ]咔唑前体的DIBAL-H促进的还原开环会导致异戊烯基和Geranylated咔唑-1,4-醌生物碱murrayaquinone-B,-C,-D和-E,并导致murrayafoline- B. 我们描述了murrayafoline-B和七个咔唑-1,4-醌生物碱的总合成。钯(II)催化的氧化环化反应可用于构建咔唑骨架。吡喃环化和氧化提供吡喃醌-A,-B和-C。吡喃并[3,2- a ]咔唑前体的DIBAL-H促进的还原开环会导致异戊烯基和Geranylated咔唑-1,4-醌生物碱murrayaquinone-B,-C,-D和-E,并导致murrayafoline-
Total synthesis of the cyclic monoterpenoid pyrano[3,2-<i>a</i>]carbazole alkaloids derived from 2-hydroxy-6-methylcarbazole
作者:Cemena Gassner、Ronny Hesse、Arndt W. Schmidt、Hans-Joachim Knölker
DOI:10.1039/c4ob01151a
日期:——
The synthesis of seven pyrano[3,2-a]carbazole alkaloids has been achieved using their putative biogenetic precursor 2-hydroxy-6-methylcarbazole as key intermediate.
Efficient Construction of Pyrano[3,2-<i>a</i>]carbazoles: Application to a Biomimetic Total Synthesis of Cyclized Monoterpenoid Pyrano[3,2-<i>a</i>]carbazole Alkaloids
作者:Ronny Hesse、Konstanze K. Gruner、Olga Kataeva、Arndt W. Schmidt、Hans-Joachim Knölker
DOI:10.1002/chem.201301792
日期:2013.10.11
We have developed a highly efficient route to 2‐hydroxy‐3‐methylcarbazole (1) via a palladium‐catalyzed construction of the carbazole skeleton. Using 1 as relay compound, different methods for annulations of pyran rings by reaction with terpenoid building blocks have been tested. The Lewis acid promoted reaction of 1 with prenal (21) opened up an efficient route to girinimbine (3) and the corresponding
我们已经开发了一种通过钯催化的咔唑骨架构建2-羟基-3-甲基咔唑(1)的高效途径。使用1作为中继化合物,已经测试了通过与萜类结构单元反应而使吡喃环环化的不同方法。路易斯酸促进的1与醛(21)的反应开辟了一条生成吉利比滨(3)的有效途径,相应的与柠檬醛(25)的反应得到了马哈宁(5)。化合物3和5的氧化提供了murrayacine(4)和murrayacinine(6)。根据生物遗传学的建议,马哈宁(5)已被用于有效的仿生合成环化单萜吡喃并[3,2– a ]咔唑生物碱环马哈宁(7),马尼苯丁(8)和双环马哈宁(9)。的互变5,7,8和9中描述和机械影响进行了讨论。通过X射线晶体结构确定明确地验证了结构分配。此外,将环马哈宁滨(7)转化为murrayazolinine(10)和exozoline(11)。
Preparation of 1,2-Dienes by the Palladium-Catalyzed Hydrogenolysis of 3-Methoxycarbonyloxy-1-alkynes with Ammonium Formate
作者:Jiro Tsuji、Teruo Sugiura、Ichiro Minami
DOI:10.1055/s-1987-28020
日期:——
A useful preparative method for 1,2-dienes from 3-methoxy-carbonyloxy-1-alkynes by the palladium-catalyzed hydrogenolysis with ammonium formate is described. 3-Methoxycarbonyloxy-1-alkynes are prepared by the addition of magnesium acetylide to ketones or aldehydes, followed by quenching with methyl chloroformate.
Two 2H-chromenes having a fully substituted benzene ring, 8-chlorocannabiorcichromene (1) and mycochromenicacid (2), were synthesized by a condensation of salicylaldehydes with isopropylidenemalonate or the thermal cyclization of corresponding propargyl ethers.