14917-83-0Relevant academic research and scientific papers
Aromatic annulation of alicyclic α,β-unsaturated aldehydes: Synthesis of chirally substituted tetrahydronaphthalenes
Brenna, Elisabetta,Fuganti, Claudio,Serra, Stefano
, p. 365 - 366 (1998)
Chiral 2-tetrahydronaphthalene-carboxylic acid derivatives 3, 6, and 9 were prepared by functionalization of enantiopure terpenic unsaturated aldehydes 1, 4, 7 with triphenyl-(α-carbethoxy-β-carboxyethyl)-phosphonium betaine, followed by a cyclization reaction promoted by ethyl chloroformate under basic conditions.
Stereoselective synthesis of carane-based chiral β- And γ-amino acid derivatives via conjugate addition
Szakonyi, Zsolt,Csor, árpád,Haukka, Matti,Fül?p, Ferenc
, p. 4846 - 4852 (2015)
Michael addition of dibenzylamine to (-)-tert-butyl isochaminate, prepared in three steps from (-)-perillaldehyde, furnished a carane-based β-amino acid derivative in a highly stereospecific reaction. The resulting amino ester was transformed to the bicyclic amino acid, a promising building block for the synthesis of 1,3-heterocycles and peptidomimetics. The conjugate addition of nitromethane to α,β-unsaturated methyl ester likewise resulted in nitro esters in stereospecific reactions. Catalytic reduction of the nitro group yielded a γ-amino ester. Under acidic conditions, the hydrolysis of the methyl ester resulted in an unexpected aminolactone-type product through rearrangement of the bicyclic carane system, whereas an alternative synthetic pathway through α,β-unsaturated benzyl ester furnished the desired γ-amino acid.
Stereoselective Synthesis and Modelling-Driven Optimisation of Carane-Based Aminodiols and 1,3-Oxazines as Catalysts for the Enantioselective Addition of Diethylzinc to Benzaldehyde
Szakonyi, Zsolt,Cs?r, árpád,Csámpai, Antal,Fül?p, Ferenc
, p. 7163 - 7173 (2016/05/19)
The reductive amination of (-)-2-carene-3-aldehyde, prepared in two steps from (-)-perillaldehyde, furnished 2-carene-based allylamines. tert-Butyloxycarbonyl (Boc) or carbobenzyloxy (Cbz) protection of the resulting amines, followed by stereoselective dihydroxylation in highly stereospecific reactions with OsO4 and subsequent deprotection, resulted in N-benzylaminodiols, which were transformed to primary and tertiary aminodiols. The reactions of the N-benzyl- and N-(1-phenylethyl)-substituted derivatives with formaldehyde led to highly regioselective ring closure, resulting in carane-fused 1,3-oxazines. The aminodiols and their 1,3-oxazine derivatives were applied as chiral catalysts in the enantioselective addition of diethylzinc to aldehydes. The best (R) enantioselectivity was observed in the case of the N-((R)-1-phenylethyl)-substituted aminodiol, whereas the opposite chiral direction was preferred when the 1,3-oxazines were applied. Through the use of molecular modelling at an ab initio level, this phenomenon was interpreted in terms of competing reaction pathways. Molecular modelling at the RHF/LANL2DZ level of theory was successfully applied for a mechanism-based interpretation of the stereochemical outcome of the reactions leading to the development of further 1,3-oxazine-based ligands, which display excellent (S) enantioselectivity (95 and 98 % ee) in the examined transformation.
Seven-Ring Annulation: A Linch-Pin Approach to a Tetracyclic Precursor of the Lathrane Diterpenes
Braish, T. F.,Saddler, J. C.,Fuchs, P. L.
, p. 3647 - 3658 (2007/10/02)
The synthesis of a chiral tetracyclic intermediate (5b) as a precursor of the lathrane diterpenes is described.The key step is the addition of chiral thioacetal 47 to a chiral vinyl sulfone 40 in the abscence of HMPA.Further elaboration of the resulting intermediate 59 provided enol ether 67, which was cyclized with dimethyl(methylthio)sulfonium tetrafluoroborate to give the tetracyclic intermediate 5b.
