Untitled

Mikulás, Mark; Möller, Christian; Rust, Sybille; Wierschem, Frank; Amrhein, Patrick; Rück‐Braun, K.

doi:10.1002/1521-3897(200010)342:8<791::aid-prac791>3.3.co;2-n

Cited by 3 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rück-Braun and coworkers have also employed triflate as the leaving group to prepare [102] cyclohexene carbaldehyde Fp complexes (Scheme 35). Reaction of the Fp anion with ␤-trifluoromethyl(sulfonyloxy)-substituted cyclic enals provided the complexes in 48-57% yield.…”

Section: Fe-c (Sp 2 ) Bond Formation (Tables 4 and 5)mentioning

confidence: 99%

Recent chemistry of the η5-cyclopentadienyl dicarbonyl iron anion

Theys

Dudley

Hossain

2009

Coordination Chemistry Reviews

View full text Add to dashboard Cite

Section: Fe-c (Sp 2 ) Bond Formation (Tables 4 and 5)mentioning

confidence: 99%

Recent chemistry of the η5-cyclopentadienyl dicarbonyl iron anion

Theys

Dudley

Hossain

2009

Coordination Chemistry Reviews

View full text Add to dashboard Cite

“…With compound 17 in hand, the key palladium-catalyzed carbonylation 20 was then performed in the presence of carbon monoxide, giving the lactone 6 with the newly formed ring D in 85% yield with 98% ee after crystallization. Notably, compared with the previous use of Pd(PPh 3 ) 4 as a catalyst in similar procedures reported by Yang 21 and Mikulas, 22 the cheap and air-stable Pd(OAc) 2 as a catalyst 23 was found to be effective in this titled carbonylationlactonization. The next step is to introduce an isopropyl group on ring A (Scheme 3).…”

mentioning

confidence: 57%

New facile enantio- and diastereo-selective syntheses of (−)-triptonide and (−)-triptolide

Zhang

Xue

et al. 2014

Org. Biomol. Chem.

View full text Add to dashboard Cite

A novel formal asymmetric synthesis of (-)-triptonide and (-)-triptolide, featuring a new alternative access to their known key intermediate 4, has been achieved through two synthetic routes in 9 steps with 13.6% total yield and 10 steps with 18.5% overall yield, respectively. This synthesis is scalable and hence has high potential for application to further synthetic elaboration and biologic investigation on such natural products.

show abstract

“…The first step is an esterification, followed by oxidation of both hydroxy groups to give methyl 3,12-dioxo-5-cholan-24-oate (B) (see Scheme 2), which was selectively chloroformylated on the A ring using Vilsmeier's reagent in chloroform solution. The molecular and supramolecular structure of compound (IV) is reported here, together with those of two analogues, whose syntheses have been reported previously, namely 3-chloro-2-formyl-17-oxo-5-cholest-2-ene [(5S,8R,9S,10S,13S,14S)-3-chloro-10,13-dimethyl-17-oxo-4,5,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthrene-2-carbaldehyde], (II) (Ruiz et al, 2013), and 3-chloro-2-formyl-5-cholest-2-ene [(5S,8R,9S,10S,13S,14S)-3-chloro-10,13-dimethyl-17-oxo-4,5,-6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta-[a]phenanthrene-2-carbaldehyde], (III) (Mikulá s et al, 2000) ( Figs. 1-3).…”

Section: Introductionmentioning

confidence: 84%

“…395-397 K (no literature m.p. reported;Mikulá s et al, 2000). Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation, at ambient temperature and in the presence of air, of solutions in chloroform-methanol (initially 1:…”

Section: Synthesis and Crystallizationmentioning

confidence: 99%

Chloro–formyl steroids as precursors for hybrid heterosteroids: synthesis, spectroscopic characterization, and molecular and supramolecular structures

et al. 2018

View full text Add to dashboard Cite

Two new functionalized steroids containing both chloro and formyl substituents in ring A, and intended as precursors for the synthesis of hybrid systems, have been synthesized from ketosteroid precursors. 3-Chloro-2-formyl-17,17-dimethyl-18-nor-5α-androstane-2,13-diene, (I), and methyl 3-chloro-4-formyl-12-oxo-5β-cholan-3-ene-24-oate, C26H37ClO4, (IV), have been synthesized using Vilsmeier reactions with 17β-hydroxy-17α-methyl-5α-androstan-3-one and methyl 3,13-dioxo-5β-cholan-24-oate, respectively. These products have been fully characterized using IR spectroscopy, 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry, and in the case of (IV), a single-crystal X-ray diffraction study. Crystal structures have also been determined for the known analogues 3-chloro-2-formyl-17-oxo-5α-androst-2-ene, C20H27ClO2, (II), 3-chloro-2-formyl-5α-cholest-2-ene, C28H45ClO, (III), and the absolute and relative configurations are assigned for all four compounds (I)–(IV): when the fusion between rings A and B is trans, 3-chloro-2-formyl products are formed, but when this ring fusion is cis, a 3-chloro-4-formyl product results. The formation of (I) involves not only chloroformylation at ring A, but also dehydration and the 1,2 migration of a methyl group at ring D. In each of (II), (III) and (IV), rings B and C adopt almost perfect chair conformations, while ring A adopts a half-chair conformation. Ring D adopts an envelope conformation in each of (II) and (III), albeit differently folded in the two compounds, while in (IV), it adopts a half-chair conformation. A single C—H...O hydrogen bond links the molecules of (II) into C(6) chains which are linked into sheets by means of carbonyl–carbonyl interactions. The molecules of (IV) are linked into simple C(7) chains, again by a single C—H...O hydrogen bond, but there are no direction-specific interactions in (III) that are structurally significant.

show abstract

Untitled

Cited by 3 publications

References 0 publications

Recent chemistry of the η5-cyclopentadienyl dicarbonyl iron anion

Recent chemistry of the η5-cyclopentadienyl dicarbonyl iron anion

New facile enantio- and diastereo-selective syntheses of (−)-triptonide and (−)-triptolide

Chloro–formyl steroids as precursors for hybrid heterosteroids: synthesis, spectroscopic characterization, and molecular and supramolecular structures

Contact Info

Product

Resources

About