18636-54-9Relevant articles and documents
A novel reaction of titanacyclopentenes and aldehydes with or without Lewis acids
Hu, Qiaoshu,Li, Dongzhen,Zhang, Huijun,Xi, Zhenfeng
, p. 6167 - 6170 (2007)
Oxatitanacyclopentenes were prepared in high yields from the reaction of aldehydes with titanacyclopenetens via substitution of ethylene. No insertion product was obtained in this reaction. The combination of alkynes and aldehydes played an important role in the successive formation of oxatitanacyclopentenes. Some oxatitanacyclopentenes are very stable and can be purified using column chromatography. The cooperation between Ti and LA led to very different results from that between Zr and LA.
Hydrogen Bonding Networks Enable Br?nsted Acid-Catalyzed Carbonyl-Olefin Metathesis**
Anh To, Tuong,Pei, Chao,Koenigs, Rene M.,Vinh Nguyen, Thanh
, (2022/02/17)
Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen-bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl-olefin metathesis reactions by hydrogen-bonding-assisted Br?nsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para-toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Br?nsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.
Palladium-Catalyzed Intramolecular Trost–Oppolzer-Type Alder–Ene Reaction of Dienyl Acetates to Cyclopentadienes
Bankar, Siddheshwar K.,Singh, Bara,Tung, Pinku,Ramasastry
supporting information, p. 1678 - 1682 (2018/02/06)
A new approach to the synthesis of highly substituted cyclopentadienes, indenes, and cyclopentene-fused heteroarenes by means of the Pd-catalyzed Trost–Oppolzer-type intramolecular Alder–ene reaction of 2,4-pentadienyl acetates is described. This unpreced
Selective Divergent Synthesis of Indanols, Indanones, and Indenes via Acid-Mediated Cyclization of (Z)- and (E)-(2-Stilbenyl)methanols and Its Application for the Synthesis of Paucifloral F Derivatives
Jongcharoenkamol, Jira,Chuathong, Patsapon,Amako, Yuka,Kono, Masato,Poonswat, Kasam,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 13184 - 13210 (2018/11/02)
Starting from bromo/iodobenzaldehyde derivatives, the corresponding (Z)- and (E)-(2-stilbenyl)methanols could be prepared in 2-5 steps via Pd-catalyzed cross-coupling reactions (Sonogashira and Heck reactions) followed by aryllithium/aryl Grignard addition. For the (E)-stilbenes, subsequent acid-mediated cyclization using p-TsOH immobilized on silica (PTS-Si) at low temperatures furnished the 2,3-trans-1-indanols with complete stereocontrol at the C2-C3. Further oxidization of the alcohol provided the indanones, which are structurally related to the natural product paucifloral F. At higher temperatures, 1,2- and 2,3-disubstituted indenes could be selectively prepared in good to excellent yields. On the other hand, the (Z)-stilbenes, under similar conditions (PTS-Si), did not give the indanols; only the 1,2-disubstituted indenes could be obtained. To gain further insights into the stereochemistry at C2-C3 for the (Z)-stilbenes, hydride or azide was employed as a nucleophile; the corresponding indane products were obtained with the cis stereochemistry at the C2-C3. Thus, the (Z)- or (E)-olefin geometry of the substrate directed the stereoselective indanyl cyclization to furnish the cis or trans at the C2-C3 ring junction, respectively, while reaction conditions controlled the selectivity of the product types.
The synthesis of 1,2-diarylindenes via DDQ-mediated dehydrogenative intramolecular cyclization
Li, Yi,Cao, Li,Luo, Xiaoyan,Deng, Wei-Ping
, p. 5974 - 5979 (2015/03/30)
A direct DDQ-mediated dehydrogenative intramolecular cyclization of (Z)-1,2,3-triaryl substituted propylenes promoted by Cu(OAc)2 was developed, providing 1,2-diarylindene derivatives in moderate to good yields (up to 92%) under mild conditions
Synthesis of substituted 2-arylindanes from e -(2-stilbenyl)methanols via lewis acid-mediated cyclization and nucleophililc transfer from trialkylsilyl reagents
Sarnpitak, Pakornwit,Trongchit, Kanokrat,Kostenko, Yulia,Sathalalai, Supaporn,Gleeson, M. Paul,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 8281 - 8296 (2013/09/24)
A preparative method for the synthesis of functionalized 2-arylindanes has been developed via the Lewis acid-mediated ring closure of stilbenyl methanols followed by nucleophilic transfer from trialkylsilyl reagents. The reactions gave the corresponding p
Au-catalyzed isomerization of cyclopropenes: a novel approach to indene derivatives
Li, Changkun,Zeng, Yi,Wang, Jianbo
scheme or table, p. 2956 - 2959 (2009/08/09)
AuPPh3Cl/AgOTf-catalyzed reaction of cyclopropenes is found to be highly efficient, giving indene derivatives in high yields. The reaction is suggested to proceed through gold vinyl carbenoid intermediate.
Reactions of unsaturated azides, 12[≠] azido-1,2,3-triphenylpropenes of varying stabilities: A corrigendum of structure assignment
Banert, Klaus,Hagedorn, Manfred,Liedtke, Christine,Melzer, Antje,Schoeffler, Claudia
, p. 257 - 267 (2007/10/03)
A reinvestigation of the reaction between 2,3-diphenyl-2-H-azirine (1) and phenyldiazomethane (2) has shown that a literature report has to be corrected since no vinyl azide 4 but rather the allylic compound 3-azido- 1,2,3-triphenyl-1-propene (3) is produced. This stable substance, which can also be prepared by substitution reactions of allylic bromide (E)-10 or from alcohol (E)-11, may be separated into its geometrical isomers (E)-3 and (Z)- 3, although these equilibrate through rapid [3,3] sigmatropic migration of the azido group. Attempts to synthesize 4 by dehydration of azido alcohols 7 using methanesulfonyl chloride and sulfur dioxide or by elimination of hydrogen chloride from azides 15 led only to 3 and 2-benzyl-2,3-diphenyl-2H- azirine (14). This heterocycle, which can also be prepared by Neber rearrangement, has been found to be the thermal and photochemical decomposition product of the unstable vinyl azides 4. However, dehydrations of 7 using thionyl chloride at low temperature have led to the first isolation of 1-azido-1,2,3-triphenyl-1-propenes (4). Starting with 3 and various other allylic azides, rearrangement reactions involving sigmatropic shift of the azido group or photochemical cis-trans isomerization have been investigated, as have base-catalyzed (prototropic) rearrangements to give vinyl azides.
Metal-catalyzed cyclopropene rearrangements for benzannulation: Evaluation of an anthraquinone synthesis pathway and reevaluation of the parallel approach via carbene-chromium complexes
Semmelhack,Ho, Suzzy,Cohen,Steigerwald,Lee,Lee,Gilbert, Adam M.,Wutff, William D.,Ball, Richard G.
, p. 7108 - 7122 (2007/10/02)
The reaction of 3-arylcyclopropenes with Cr(CO)6 and Mo(CO)6 produces naphthols, in an example of metal-promoted benzannulation. Substituents at C- 3 (in addition to aryl) have a strong effect on the success of the process: 3-H deriv
