4397-05-1Relevant articles and documents
Expeditious and practical synthesis of tertiary alcohols from esters enabled by highly polarized organometallic compounds under aerobic conditions in Deep Eutectic Solvents or bulk water
Quivelli, Andrea F.,D'Addato, Giovanna,Vitale, Paola,García-álvarez, Joaquín,Perna, Filippo M.,Capriati, Vito
, (2021/01/18)
An efficient protocol was developed for the synthesis of tertiary alcohols via nucleophilic addition of organometallic compounds of s-block elements (Grignard and organolithium reagents) to esters performed in the biodegradable choline chloride/urea eutectic mixture or in water. This approach displays a broad substrate scope, with the addition reaction proceeding quickly (20 s reaction time) and cleanly, at ambient temperature and under air, straightforwardly furnishing the expected tertiary alcohols in yields of up to 98%. The practicability of the method is exemplified by the sustainable synthesis of some representative S-trityl-L-cysteine derivatives, which are a potent class of Eg5 inhibitors, also via telescoped one-pot processes.
Selective reaction of benzyl alcohols with HI gas: Iodination, reduction, and indane ring formations
Matsumoto, Shoji,Naito, Masafumi,Oseki, Takehisa,Akazome, Motohiro,Otani, Yasuhiko
, p. 7254 - 7259 (2017/11/24)
Reactions of benzyl alcohols with HI in solvent-free conditions were examined. Three types of reactions (iodination, reduction, and ring formation) occurred depending on the degree of crowding around the benzyl position and the benzylic stabilization of substrates. Results also showed that the ring formation to give indanes proceeded efficiently when HI was used, and that compounds with electron-rich aromatic rings gave indane derivatives in good yields.
Zinc(ii)-catalyzed Grignard additions to ketones with RMgBr and RMgI
Hatano, Manabu,Ito, Orie,Suzuki, Shinji,Ishihara, Kazuaki
scheme or table, p. 2674 - 2676 (2010/07/08)
Highly efficient alkylations and arylations of ketones with Grignard reagents (RMgBr and RMgI) have been developed using catalytic ZnCl2, Me3SiCH2MgCl, and LiCl. Tertiary alcohols were obtained in high yields with high chemoselectivities, while minimizing undesired side products produced by reduction and enolization.
Zinc(II)-catalyzed addition of grignard reagents to ketones
Hatano, Manabu,Ito, Orie,Suzuki, Shinji,Ishihara, Kazuaki
supporting information; experimental part, p. 5008 - 5016 (2010/10/04)
(Figure presented) The addition of organometallic reagents to carbonyl compounds has become a versatile method for synthesizing tertiary and secondary alcohols via carbon-carbon bond formation. However, due to the lack of good nucleophilicity or the presence of strong basicity of organometallic reagents, the efficient synthesis of tertiary alcohols from ketones has been particularly difficult and, thus, limited. We recently developed highly efficient catalytic alkylation and arylation reactions to ketones with Grignard reagents (RMgX: R = alkyl, aryl; X = Cl, Br, I) using ZnCl2, Me3SiCH 2MgCl, and LiCl, which effectively minimize problematic side reactions. In principle, RMgBr and RMgI are less reactive than RMgCl for the addition to carbonyl compounds. Therefore, this novel method with homogeneous catalytic ZnCl2·Me3SiCH2MgCl·LiCl is quite attractive, since RMgBr and RMgI, which are easily prepared and/or commercially available, like RMgCl, can be applied successfully. As well as ketones and aldehydes, aldimines were effectively applied to this catalysis, and the corresponding secondary amines were obtained in high yield. With regard to mechanistic details concerning β-silyl effect and salt effect, in situ-prepared [R(Me3SiCH2)2Zn] -[Li]+[MgX2]m[LiCl]n (X = Cl/Br/I) is speculated to be a key catalytic reagent to promote the reaction effectively. The simplicity of this reliable ZnCl2·Me 3SiCH2MgCl·LiCl system in the addition of Grignard reagents to carbonyl compounds might be attractive for industrial as well as academic applications.
Highly efficient alkylation to ketones and aldimines with Grignard reagents catalyzed by zinc(II) chloride
Hatano, Manabu,Suzuki, Shinji,Ishihara, Kazuaki
, p. 9998 - 9999 (2007/10/03)
A highly efficient alkylation to ketones and aldimines with Grignard reagents in the presence of catalytic trialkylzinc(II) ate complexes derived from ZnCl2 (10 mol %) in situ was developed. This simple Zn(II)-catalyzed alkylation could minimize the well-known but serious problems with the use of only Grignard reagents, which leads to reduction and aldol side products, and the yield of desired alkylation products could be improved. Copyright
Improved addition of organolithium reagents to hindered and/or enolisable ketones
Lecomte, Vincent,Stéphan, Elie,Le Bideau, Franck,Jaouen, Gérard
, p. 2169 - 2176 (2007/10/03)
A study of the addition of some aryl- and alkyllithium derivatives to some hindered and/or enolisable ketones in different solvents (polar and apolar) and, in some cases, at different temperatures and reaction times, will be presented here. The reversibility of the addition of aryllithium to these specific ketones will be observed and discussed. This approach is then used to prepare new steroids as precursor for potentially interesting substituted testosterones.
Improved addition of phenyllithium to hindered ketones by the use of non-polar media
Lecomte, Vincent,Stéphan, Elie,Jaouen, Gérard
, p. 3463 - 3465 (2007/10/03)
The use of a non-polar medium at room temperature is an efficient, cheap and easy way to improve the low reactivity of six hindered ketones towards phenyllithium.
On rearrangements by cyclialkylations of arylpentanols to 2,3-dihydro-1H-indene derivatives. Part 2. An unexpected rearrangement by the acid-catalyzed cyclialkylation of 2,4-dimethyl-2-phenylpentan-3-ol under formation of trans-2,3-dihydro-1,1,2,3-tetramethyl-1H-indene
Giovannini, Edgardo,Hengartner, Urs,Pasquier, Pierre
, p. 1841 - 1849 (2007/10/03)
The acid catalyzed-cyclialkylation of 4-(2-chloro-phenyl)-2,4-dimethylpentan-2-ol (1) gave two products: 4-chloro-2,3-dihydro-1,1,3,3-tetramethyl-1H-indene (2) and also trans-4-chloro-2,3-dihydro-1,1,2,3-tetramethyl-1H-indene (3). A mechanism was proposed in Part 1 (cf. Scheme 1) for this unexpected rearrangement. This mechanism would mainly be supported by the result of the cyclialkylation of 2,4-dimethyl-2-phenylpentan-3-ol (4), which, with respect to the similarity of ion II in Scheme I and ion V in Scheme 2, should give only product 5. This was indeed the experimental result of this cyclialkylation. But the result of the cyclialkylation of 1,1,1,2′,2′,2′-hexadeuterated isomer [2H6]-4 of 4 (cf. Scheme 3) requires a different mechanism as for the cyclialkylation of 1. Such a mechanism is proposed in Schemes 5 and 6. It gives a satisfactory explanation of the experimental results and is supported by the result of the cyclialkylation of 2,4-dimethyl-3-phenylpentan-3-ol (9; Scheme 7). The alternative migration of a Ph or of an i-Pr group (cf. Scheme 6) is under further investigation.
Substituent effect on the solvolysis of α-t-butyl-α-methylbenzyl chlorides
Fujio, Mizue,Nomura, Hideyuki,Nakata, Kazuhide,Saeki, Yoshihiro,Mishima, Masaaki,Kobayashi, Shinjiro,Matsushita, Toshio,Nishomoto, Kichisuke,Tsuno, Yuho
, p. 5005 - 5008 (2007/10/02)
The substituent effect on the solvolysis rates of α-t-butyl-α- methylbenzyl chlorides in 80% aq. acetone was correlated to give p=-4.3 and r=0.91 in terms of the LArSR Eq. (1). This slightly reduced r value relative to full conjugation corresponds to a deviation by 0=24.5° from the coplanarity of the benzylic π-system.
