Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and ⁶Li/¹³C NMR spectroscopic data

• Jürgen Vollhardt,
• Hans Jörg Lindner and
• Hans-Joachim Gais

Beilstein J. Org. Chem. 2020, 16, 2057–2063, doi:10.3762/bjoc.16.172

• couplings shows, however, that the carbon lithium bonds in 2a-I have a covalent contribution as generally observed for organolithiums [55]. Three mechanisms most likely contribute to the stabilization of the negative charge of the carbon atoms of tetramer (2a)4·(THF)6 and hexamer (2a)6·Li2O·(THF)6

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• be stressed that this kind of sequential transformations are practically impossible to perform using conventional batch chemistry because of the incompatibility of sensitive functional groups with organolithiums, and because of the high chemical and thermal instability of the intermediates. In 2015

• -butyl esters, avoiding the use of inflammable and explosive gaseous isobutylene [35], the use of harsh conditions [36], the use of peroxides [37], the use of toxic gas such as CO or transition metals [38][39][40][41][42]. The flow process, for the direct C-tert-butoxycarbonylation of organolithiums, has

• been optimized in a green solvent such as 2-MeTHF by a precise control of the residence time, and without using cryogenic conditions (Scheme 6). In addition, many organolithiums were generated from the corresponding halo compounds by a halogen/lithium exchange reaction using hexyllithium as a more

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• is proposed (Scheme 29) [135][136]. Such a pathway could also apply for the reductive decyanation of diphenylacetonitriles induced by organolithiums or Grignard reagents [137][138]. This reaction, applied to nitriles substituted with suitable leaving groups appears as a cyanation method of

Microsolvation and sp²-stereoinversion of monomeric α-(2,6-di-tert-butylphenyl)vinyllithium as measured by NMR

• Rudolf Knorr,
• Monika Knittl and
• Eva C. Rossmann

Beilstein J. Org. Chem. 2014, 10, 2521–2530, doi:10.3762/bjoc.10.263

• traditional methods of molecular mass determinations that measure the averaged colligative properties of a solution. Fortunately, the 13C NMR techniques [5] exemplified further below can identify the ground-state structures of organolithiums even in partially decayed or contaminated solutions. However, the

Carbolithiation of N-alkenyl ureas and N-alkenyl carbamates

• Julien Lefranc,
• Alberto Minassi and
• Jonathan Clayden

Beilstein J. Org. Chem. 2013, 9, 628–632, doi:10.3762/bjoc.9.70

• in an enamine carbolithiation reaction [9]. Similar reactivity is observed with related O-carbamoyl enols [10][11][12]. The organolithium resulting from the enamine carbolithiation is nucleophilic at the atom α to nitrogen, and such carbolithiations have been used to generate hindered organolithiums

• by protonation, carbolithiated products 2a and 2b were isolated in good yield (Scheme 1 and Table 1, entries 1 and 2). Similar reactivity was observed between urea 1a and less hindered organolithiums such as iPrLi or n-BuLi [3], but in THF even at −78 °C a rearrangement [14][15][16][17][18] of the

Intramolecular carbolithiation cascades as a route to a highly strained carbocyclic framework: competition between 5-exo-trig ring closure and proton transfer

• William F. Bailey and
• Justin D. Fair

Beilstein J. Org. Chem. 2013, 9, 537–543, doi:10.3762/bjoc.9.59

• reaction appears to provide an interesting … procedure for formation of five-membered ring systems which is potentially significant for synthetic purposes” [3]. Indeed, the facile cyclization of olefinic and acetylenic organolithiums has proven to be a regiospecific and highly stereoselective route [4] to

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• the energetic barriers are of the magnitude of the activation energies of the competing diastereomorphic addition steps. In the presence of (–)-sparteine (L1), N-alkenyl-N-arylureas 17 undergo addition of organolithiums to generate stabilized benzyllithiums, in which a N to C aryl transfer occurs by

• resulting organolithiums can be trapped with different electrophiles to afford allenes 24 with complete regioselectivity and good yields. The best ee is obtained when there is a carbamoyloxy group (CbO) as directing group in the substrate with (−)-sparteine (L1) as the chiral ligand (Scheme 8) [27]. Despite

• enantioselectivity. The addition of TMEDA increases the rate of racemization, resulting in an inversion of diastereoselectivity to obtain 36, albeit in racemic form [44]. The enantioselective cycloisomerization of achiral organolithiums in the presence of a chiral ligand has been reported with aryllithium reagents

Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

• David. M. Hodgson and
• Rosanne S. D. Persaud

Beilstein J. Org. Chem. 2012, 8, 1896–1900, doi:10.3762/bjoc.8.219

• Cy3P did not lead to the orange–red colouration suggestive of ylide formation, and only starting epoxide 11 was observed. We also studied the possibility of generating alcohol 7 from terminal epoxide 11 using an organolithium instead of a hindered lithium amide as the base (Scheme 5). Organolithiums

• , in particular secondary and tertiary organolithiums, are known to react with terminal epoxides by α-lithiation, although this is typically followed by trapping of the α-lithiated epoxide with a second equivalent of the organolithium and elimination of Li2O to give an E-alkene (e.g., 12): a process

• ~60% Ph3P being recovered. The highest yield of allylic alcohol 7 (18%) was obtained by using s-BuLi in Et2O at −78 °C with a 24 h lithiation time (Scheme 5); lithiation by using other organolithiums (t-BuLi, PhLi, BuLi, MeLi), or at higher or lower temperatures (−90 °C or −40 °C), for a longer period

Carbamate-directed benzylic lithiation for the diastereo- and enantioselective synthesis of diaryl ether atropisomers

• Abigail Page and
• Jonathan Clayden

Beilstein J. Org. Chem. 2011, 7, 1327–1333, doi:10.3762/bjoc.7.156

• organolithiums may again be to blame. Enantiomerically enriched stannane returned enantiomerically enriched product, showing that racemisation (which necessarily involves either rotation about the Ar–O–Ar axis or deprotonation–reprotonation) is also slow. Discussion Due to the gummy nature of the products, it

• turned out to be impossible to establish unequivocally the relative or absolute stereochemistry of the products obtained from the lithiations. However, we can make several important conclusions from this work. Firstly, racemisation of the intermediate organolithiums is demonstrably slow, because an

• -(−)-sparteine deprotonation step. Secondly, since epimerisation of the organolithiums is also slow enough for different d.r.'s of a stananne to yield different d.r.'s of a product (Table 3, entries 1 and 3), we can be certain that the secondary benzyllithium centre is macroscopically stable on the timescale of

Selectivity in C-alkylation of dianions of protected 6-methyluridine

• Ngoc Hoa Nguyen,
• Christophe Len,
• Anne-Sophie Castanet and
• Jacques Mortier

Beilstein J. Org. Chem. 2011, 7, 1228–1233, doi:10.3762/bjoc.7.143

• organolithiums [14], and indeed, 7 failed to react, in our experiments, with 4-bromo-but-1-ene to give 9. We then turned our attention to the metalation of the 5'-O-TBDMS protected nucleoside 10 (Figure 2). Treatment with LDA (5 equiv) in THF at −70 °C followed by addition of D2O provided 12 in 82% yield

Homocoupling of aryl halides in flow: Space integration of lithiation and FeCl₃ promoted homocoupling

• Aiichiro Nagaki,
• Yuki Uesugi,
• Yutaka Tomida and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2011, 7, 1064–1069, doi:10.3762/bjoc.7.122

• salts; microreactor; organolithiums; Introduction Biaryl structures often occur in various organic compounds including natural products, bioactive compounds, functional polymers, ligands in catalysts and theoretically interesting molecules, and the oxidative homocoupling of arylmetals is one of the

• ][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85] are quite effective for the generation and reaction of highly reactive organolithiums such as functionalized aryllithiums

Asymmetric synthesis of tertiary thiols and thioethers

• Jonathan Clayden and
• Paul MacLellan

Beilstein J. Org. Chem. 2011, 7, 582–595, doi:10.3762/bjoc.7.68

• was also configurationally stable in diethyl ether and TMEDA at −78 °C [66][67]. Reaction with a series of electrophiles allowed isolation of functionalised thiocarbamates 83 in excellent yield and enantiomeric ratio (Scheme 29). Benzylic organolithiums are notorious for the lack of consistency with

α,β-Aziridinylphosphonates by lithium amide-induced phosphonyl migration from nitrogen to carbon in terminal aziridines

• David. M. Hodgson and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2010, 6, 978–983, doi:10.3762/bjoc.6.110

• substrate 1a (57%, Scheme 4) [28]. Initially, we examined organolithiums for their propensity to induce deprotonation-migration in N-phosphonate aziridine 1a. Despite it being previously noted by Zwierzak that the reaction of organolithium reagents with such substrates resulted in preferential attack at

An exceptional P-H phosphonite: Biphenyl- 2,2'-bisfenchylchlorophosphite and derived ligands (BIFOPs) in enantioselective copper- catalyzed 1,4-additions

• T. Kop-Weiershausen,
• J. Lex,
• J.-M. Neudörfl and
• B. Goldfuss

Beilstein J. Org. Chem. 2005, 1, No. 6, doi:10.1186/1860-5397-1-6

• -ethylcyclohexanone with 11% ee (Table 3). Apparently, the higher Lewis acidity of organozincs supports faster nucleophilic substitution in (1) than with organolithiums (Table 1). Unprecedented however is the P-H phosphonite BIFOP-H (3), which yields with 65 % ee a much higher enantioselectivity than the