1944-01-0Relevant academic research and scientific papers
Naphthalene-Catalysed Reductive Desulfonylation with Lithium: Alkyllithiums from Alkyl Phenyl Sulfones
Guijaro, David,Yus, Miguel
, p. 2965 - 2968 (1994)
The reaction of alkyl aryl sulfones 1 with an excess of lithium powder and a catalytic amount of naphthalene (8 mol percent) in the presence of a carbonyl compound iCHO, PhCHO, Et2CO, (CH2)5CO> or trimethylchlorosilane (Barbier-type conditions) in THF at temperatures ranging between -78 and 20 deg C leads, after hydrolysis with water, to the expected coupling products, arising from the corresponding alkyllithium in situ generated, in 30-61percent yields.
Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
supporting information, p. 6169 - 6172 (2021/06/30)
Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
supporting information, p. 5611 - 5615 (2019/08/01)
The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
PROCESS FOR PREPARING ARYL KETONE
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Paragraph 0160; 0161, (2017/06/12)
A process for preparing aryl ketones is disclosed. The process includes photo-oxidizing a compound of formula (V), (VI), (VII) or (VIII): in the presence of an oxidative system comprising at least one bromide compound to form aryl ketones. X1, X2, R1, R2, R3, L1, L2, L3, L4, t, n, m and p have the meanings as described in the specification and claims.
Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
Wang, Haining,Dai, Xi-Jie,Li, Chao-Jun
, p. 374 - 378 (2017/04/03)
Nucleophilic addition reactions of organometallic reagents to carbonyl compounds for carbon-carbon bond construction have played a pivotal role in modern chemistry. However, this reaction's reliance on petroleum-derived chemical feedstocks and a stoichiometric quantity of metal have prompted the development of many carbanion equivalents and catalytic metal alternatives. Here, we show that naturally occurring carbonyls can be used as latent alkyl carbanion equivalents for additions to carbonyl compounds, via reductive polarity reversal. Such 'umpolung' reactivity is facilitated by a ruthenium catalyst and diphosphine ligand under mild conditions, delivering synthetically valuable secondary and tertiary alcohols in up to 98% yield. The unique chemoselectivity exhibited by carbonyl-derived carbanion equivalents is demonstrated by their tolerance to protic reaction media and good functional group compatibility. Enantioenriched tertiary alcohols can also be accessed with the aid of chiral ligands, albeit with moderate stereocontrol. Such carbonyl-derived carbanion equivalents are anticipated to find broad utility in chemical bond formation.
The Barbier-Grignard-Type Arylation of Ketones and Unexpected Cross-Coupling of Phenolic Ketones using Unactivated Aryl Bromides
Wen, Yunming,Chen, Guifang,Huang, Shiqiang,Tang, Yu,Yang, Jun,Zhang, Yuanming
, p. 947 - 957 (2016/04/05)
A novel, highly versatile and efficient method has been developed for the Barbier-Grignard-type arylation of ketones and an unexpected cross-coupling of phenolic ketones was observed using unactivated bromides and magnesium in tetrahydrofuran/toluene at 96°C promoted by multicatalysts of cupric bromide (15 mol%), bismuth chloride (5 mol%) and silver bromide (10 mol%). The substituent and electronic effects on the reaction have been discussed. High yields of arylation and cross-coupling have been attained under mild conditions. A novel reasonable mechanism involving a quinone intermediate is proposed. The high chemical selectivity in the cross-coupling to the hydroxy group of phenolic ketones should help ketones find new applications.
Exploration of the diastereoselectivity in an unusual Grignard reaction and its application towards the synthesis of styryl lactones 7-: Epi -(+)-goniodiol and 8- epi -(-)-goniodiol
Chavan, Subhash P.,Khatod, Harshali S.,Das, Tamal,Vanka, Kumar
, p. 50721 - 50725 (2016/06/09)
An unusual diastereoselective Grignard reaction is explored, where the Grignard reagents are derived from 1,n-dihaloalkanes. A steric bias due to the presence of a quaternary centre adjacent to the acetonide ester at the benzylic position is responsible for the formation of an intramolecularly reduced product in almost quantitative yield. This steric hindrance is responsible for the diastereoselectivity observed with a variety of aromatic as well as aliphatic esters. The unusual Grignard reaction furnishes long chain secondary alcohols possessing a terminal olefin, which are synthetically important intermediates. As an application of this method, the diastereoselective synthesis of styryl lactones viz. 7-epi-(+)-goniodiol (29) and 8-epi-(-)-goniodiol (30) has been achieved.
Mechanochemical ritter reaction: A rapid approach to functionalized amides at room temperature
Dokli, Irena,Gredi?ak, Matija
supporting information, p. 2727 - 2732 (2015/04/27)
A fast and efficient mechanochemical Ritter reaction between alcohols and nitriles under mild conditions is demonstrated. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using a Br?nsted acid catalyst. Its general application has been verified through a substrate screening comprising a wide range of functionalized nitriles as well as secondary and tertiary alcohols. Gentle Ritter: A fast and efficient mechanochemical Ritter reaction under mild conditions is described. The reaction proceeds rapidly at room temperature in a solvent-free or low-solvent environment by using sulfuric acid as catalyst.
A study about the synthesis of seven-membered-ring analogues of ketamine
Moghimi, Abolghasem,Shahdadi, Mohammad Reza,Keshipour, Sajjad,Sadeghzadeh, Morteza
, p. 6957 - 6966 (2015/09/29)
Synthesis of seven-membered ring analogues of ketamine was studied with two strategies. In the first approach a sequence of five reactions was used which previously applied for ketamine synthesis. This strategy led to formation of 1-[(2-chlorophenyl)(methylimino)methyl]cyclohexan-1-ol as a precursor for the target molecule. In the second approach, we have designed and attempted to synthesize a new analogue of ketamine applying challenging reactions such as ring expansion and selective bromination. The result of this route is synthesis of some interesting compounds such as 6-phenyl-1-oxa-4-thiaspiro[4.6]undecane, 3-bromo-6-phenyl-1-oxa-4-thiaspiro[4.6]undecane and 2,7-dibromo-2-phenylcycloheptanone.
Bu4N+ alkoxide-initiated/autocatalytic addition reactions with organotrimethylsilanes
Das, Manas,O'Shea, Donal F.
, p. 5595 - 5607 (2014/07/08)
The use of Me3SiO-/Bu4N+ as a general activator of organotrimethylsilanes for addition reactions has been established. The broad scope of the method offers trimethylsilanes (including acetate, allyl, propargyl, benzyl, dithiane, heteroaryl, and aryl derivatives) as bench-stable organometallics that can be readily utilized as carbanion equivalents for synthesis. Reactions are achieved at rt without the requirement of specialized precautions that are commonplace for other organometallics.
