Stille and Suzuki Cross-Coupling Reactions as Versatile Tools for Modifications at C-17 of Steroidal Skeletons - A Comprehensive Study
作者:Vanessa Koch、Martin Nieger、Stefan Bräse
DOI:10.1002/adsc.201601289
日期:2017.3.6
cross‐coupling study of steroidal vinyl (pseudo)halides with different boronic acids and tributyltin organyls. Furthermore, we have investigated the “inverse” case of those cross‐coupling reactions, i.e., the reaction of a steroidal vinylpinacolatoborane or a tributyltin steroid with various bromides. The development of both methods allows the introduction of different residues at C‐17 of steroid skeletons
Synthesis of isocoumarins via palladium catalyzed reactions of methyl 2-(2′, 2′-dibromovinyl)benzoates
作者:Le Wang、Wang Shen
DOI:10.1016/s0040-4039(98)01690-6
日期:1998.10
3-Substituted isocoumarins are synthesized in good to excellent yields via palladium catalyzed coupling of 2-(2′,2′-dibromovinyl)benzoates and organostannanes. The process involves a Stille reaction, and a subsequent annulation reaction.
congested neopentyl ketone in 10 proved to be problematic. Reaction of the enol triflate 1111 with lithium dimethylcuprate led to reduction to the disubstituted alkene without incorporation of the requisite methyl group.12 The desired alkene 12 was ultimately obtained by reaction of 11 with trimethylaluminum under Pd catalysis.13 Successful alkenylation at this sterically hindered position using palladium-mediated
Total Syntheses of Scaparvins B, C, and D Enabled by a Key C–H Functionalization
作者:Qinda Ye、Pei Qu、Scott A. Snyder
DOI:10.1021/jacs.7b06185
日期:2017.12.27
possesses an impressive range of bioactivities and high synthetic challenge due to their unique amalgamation of rings, stereocenters, and oxygenation. Herein, we disclose the first totalsyntheses of three members, scaparvins B, C, and D, through a route fueled by several chemoselective and carefully orchestrated steps. One such operation is a tailored late-stage C-H functionalization converting a carboxylic
由于环、立体中心和氧合的独特融合,克莱罗丹二萜家族具有一系列令人印象深刻的生物活性和高合成挑战。在这里,我们公开了三个成员,scaparvins B、C 和 D 的第一次全合成,通过几个化学选择性和精心策划的步骤推动的路线。一种这样的操作是在最小化烯烃环氧化的条件下通过叔CH键的氧化将羧酸转化为内酯的定制后期CH官能化。这一步提供了完成目标的关键功能。此外,使用适当的手性催化剂与拉瓦尔二烯使序列具有对映选择性。
Novel compounds of the general formula I ##STR1## and the pharmacologically tolerable addition salts thereof with acids are described, in which either Ia) R.sup.11 represents a hydrogen atom in the .beta.-configuration and each of R.sup.12 and R.sup.13 represents a hydrogen atom, or Ib) R.sup.11 represents a hydrogen atom in the .beta.-configuration and R.sup.12 and R.sup.13 together represent a second bond, or Ic) R.sup.11 and R.sup.12 together represent a second bond and R.sup.13 represents a hydrogen atom, or Id) R.sup.11 represents a hydrogen atom in the .alpha.-configuration and R.sup.12 and R.sup.13 together represent a second bond, and in Ia), Ib), Ic) or Id) X represents an oxygen atom, the hydroxyimino grouping >N.about.OH or two hydrogen atoms, R.sup.1 represents a hydrogen atom or a methyl group, R.sup.2 represents a hydroxy group, a C.sub.1 -C.sub.10 -alkoxy group or a C.sub.1 -C.sub.10 -acyloxy group, and R.sup.3 and R.sup.4 have the meanings customary for competitive progesterone antagonists specified in the description. The invention relates also to processes for the preparation of the novel compounds, to pharmaceutical compositions containing those compounds, to their use for the manufacture of medicaments, and to the novel intermediates required for the process. The novel compounds have a strong affinity for the gestagen receptor and exhibit pronounced antigestagenic and also antiglucocorticoid, antimineralocorticoid and antiandrogenic properties.