72299-82-2

Upstream product

• 54106-83-1 pent-3-ynyl triflate 
• 100-52-7 benzaldehyde 
• 109-72-8 n-butyllithium 
• 507260-96-0 5,5-dibromo-4-methyl-1-phenylpent-4-en-1-ol 
• 96-09-3 styrene oxide 
• 27163-48-0 5-acetoxy-5-phenyl-2-pentanone 
• 58193-48-9 1-phenyl-1-hydroxy-pentane-4-one 
• 636599-06-9 5,5-dibromo-4-methyl-1-phenyl-4-pentenyl acetate 
• 917-54-4 methyllithium 
• 1008-76-0 4,5-dihydro-5-phenyl-2(3H)-furanone 

Relevant academic research and scientific papers

A new method for the preparation of non-terminal alkynes: Application to the total syntheses of tulearin A and C

Lactones are known to react with the reagent generated in situ from CCl4 and PPh3 in a Wittig-type fashion to give gem-dichloro-olefin derivatives. Such compounds are now shown to undergo reductive alkylation on treatment with organolithium reagents RLi to furnish acetylene derivatives bearing the substituent R at their termini (R=Me, n-, sec-, tert-alkyl, silyl); the reaction can be catalyzed with either Cu(acac)2 or Fe(acac)3/1,2-diaminobenzene. Two alkynol derivatives prepared in this way from readily accessible lactone precursors served as the key building blocks for the total syntheses of the cytotoxic marine macrolides tulearin A (1) and C (2). The assembly of these fragile targets hinged upon ring closing alkyne metathesis (RCAM) followed by a formal trans-reduction of the resulting cycloalkynes via trans-hydrosilylation/protodesilylation.

Total synthesis of tulearin C

With the help of the smaller brother: Although alkyne metathesis will always be the little brother of alkene metathesis, it allows problems to be solved that are currently beyond reach of the more famous sibling. This notion is exemplified by the tulearin macrolides, which could only be selectively forged by ring-closing alkyne metathesis (RCAM)/transreduction using the latest generation of alkyne metathesis catalysts.

Intramolecular Substitution Reaction of Lithium Alkylidene Carbenoids. Regioselective Synthesis of Indenes

When 4,4-dibromo-3-alkenols are treated with butyllithium, an intramolecular substitution reaction with alkoxide moiety occurs at the lithium alkylidene carbenoid center to give dihydrofurans. The reaction mechanism of this intramolecular substitution reaction is studied by B3LYP density functional calculations with the 6-31+G(d) basis set, and the substitution is found to proceed in a concerted manner. This substitution reaction is applied to the regioselective preparation of indene derivatives. That is, treatment of 3-(o-bromophenyl)-1,1-dibromopropene derivatives 23 with butyllithium results in the formation of intramolecular substitution intermediates, 3-indenyllithiums D, which are trapped with electrophiles to afford substituted indenes regioselectively.

Intramolecular substitution reaction of alkylidene-lithium carbenoids: Regioselective synthesis of indenes

Intramolecular substitution reaction of geminal dibromo alkenes proceeds to afford indenes, dihydronaphthalenes, dihydrofurans, and dihydropyran via in sint generated lithium alkylidene carbenoids, which have a carbon or oxygen nucleophilic moiety. This reaction provides a regioselective method for the preparation of polysubstituted indenes.

Arene-catalysed lithiation of triflates and triflamides under Barbier-type conditions: An indirect transformation of alcohols and amines into organolithium compounds

The reaction of alkyl triflates 1 or benzyl triflamides 3 with an excess of lithium powder and a catalytic amount of naphthalene (4 mol%) in the presence of different electrophiles [Me3SiCl, Pr(i)CHO, Bu(t)CHO, PhCHO, 4-MeOC6H4-CHO, CH3(CH2)6CHO, Et2CO, (CH2)5CO, (c-C3H5)2CO, PhCOMe, 4-MeC6H4COPh, PhCh=NPh, n-C8H7CON(CH2)4] in THF at temperature ranging between -78 and 0°C leads, after hydrolysis with water, to the corresponding condensation products 2. When α,β-unsaturated carbonyl compounds are used as electrophilic compounds 1,2- (3-cyclohexenone) or 1,4-addition (cinnamaldehyde or benzylideneacetone) takes place depending on the electrophile used.