Total Synthesis of (±)-Boschnialactone and (±)-Tetrahydroanhydrodesoxyaucubigenin

A total synthesis of (±)-boschnialactone ( 1 ) and (±)-tertahydroanhydrodesoxyaucubigenin ( 2 ) is described and trisubstitued cyclopentenoid 3 is a key intermediate.     

Patchouli Fragrance Chemistry: Stereoselective Synthesis of (±)-ISO-Norpatchoulenol

A short and efficient stereoselective synthesis of (±)-iso-norpatchoulenol 3 involving, as a key step, the intramolecular trapping of a vinyl carbanion is described. The new compound has a weak characteristic odor of patchouli.     

Synthesis of (±)Dehydroxyglaupalol and Analogs

The natural furocoumarin dehydroxyglaupalol and two analogs were prepared by reaction of the appropriate 4-hydroxy-coumarin with 3-chloro-3-methylbutyne in basic medium, followed by catalytic hydrogenation of the exo double bond.     

The Total Synthesis of (±)-Hinesol and (±)-Agarospirol

Eversinceβ-vetivoneanditscongenerswererecognizedtohavespiro[4,5]decaneratherthanthehydroazuleneskeleton,[1]themembersofthisclasshavebecomeafavoritetargetforsynthesis.Herein.weshowafacileconversionofthemajorphotoproductformedinthereactionofmethyl2,4-dioxopentancate(1)with1,5-dimethyl-6-methylenecyclochexene(2)[2]intovetispiranederivatives,hinesol(3),ametaboliteofAtractylodeslancea[3,4],andagarospirol(4)foundinAquilariaagollocha,[5]inracemicforms,respectively.WhenanEtoAsolutionof1and2wasintema…     

Synthesis of (±)-Altaicadispirolactone

The first synthesis of (±) Altaicadisporolactane 1 is described starting from succinic anhydride.     

Synthesis of (±) Combretastatin

Combretastatin (1) is a new plant product isolated recently by Pettit et al ¹. from the South African tree, Combretum caffrum that possesses central nervous system antineoplastic activity and is being evaluated against several of National Cancer Institute's key evaluation systems. The structure of 1 was established on the basis of its spectral properties and confirmed by X-ray analysis. However, the absolute configuration and the synthesis of 1 have not been reported so far. As combretastatin is present in the plant in only 0.0008% and the isolation technique is much tedious, there is an urgent need for the synthesis of 1 for further evaluation of its activity. This prompted us t o report the first synthesis of (±)1.     

Efficient and Facile Synthesis of ( ± )-Salvirecognine

Salvirecognine (7) is a diterpene isolated from Salvia recognita[1] which has been the subject of continued and growing interest, due to the range of biological activities shown by many members of this family. [2] In order to study further relationships between the structure and biological activity of the diterpene compounds and as an extension of diterpenoid synthesis in our laboratory, [3,4] the first total synthesis of the title compound was achieved by an efficient and facile route (Scheme 1).     

Synthesis of (±)-zearalenone

The aliphatic portion of (±)-zearalenone has been synthesised by a new simple route starting from 2,3-dihydropyran and 2-acetyl-γ-butyrolactone by employing dithiane for C-C bond formation. The final condensation of this segment with the aromatic part and subseqnet transformations led to (±)-zearalenone.     

Synthesis of (±)-Bimatoprost

A general synthetic approach has been developed for the synthesis of a key intermediate (6) that can be elaborated into several ophthalmic prostaglandins and their derivatives. Using these strategy, we have obtained (±)-bimatoprost (1) and its analog, (±)-homobimatoprost (5).     

Photochemical Synthesis of Aporphines: (±)-Glaucine, (±)-Norglaucine and (±)-Dehydronorglaucine

Photochemical cyclization of 3 afforded 5, 4 and 8.5 on LAH reduction furnished (±)-glaucine (6) and on treatment with ethanolic HCl afforded (±)-norglaucine (7). 10 obtained by the photocyclization of 9 was converted into 7 and 11 via 12.     

A Short Synthesis of Benzomorphane Analgesics (±)-Metazocine and (±)-Phenazocine

A three step synthesis of (±)-metazocine and (±)-phenazocine starting with 3,4-lutidine is described. The key step involves Lewis acid promoted lithiation/electrophilic substitution reaction of N-alkyl-3,4-dimethyl-1,2,5,6- tetrahydropyridine.     

First Total Synthesis of(±)-Puyanin and(±)-4'-Omethylbonannione

A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids, (±)‐puyanin ( 1 ) and (±)‐4′‐O‐methylbonannione ( 2 ) has been obtained with total yields of 27% and 17.8%, respectively. The key steps were regioselective cyclization of geranylated trihydroxychalcone and regioselective geranylation of 2,4,6‐trihydroxyacetophenone.     

Total Synthesis of (±)‐Infuscol A and (±)‐Cuprenenol

Abstract

Total synthesis of the nonaromatic cuparenoid sesquiterpenes (±)‐infuscol A and cuprenenol, and (±)‐infuscol B and neocuprenenol isolated from the Japanese liverwort Jungermannia infusca has been accomplished. Two ring‐closing metathesis reaction based strategies have been developed for the generation of the key intermediate of the sequence.     

Synthesis of(±)-Deoxyschisandrin and the Corresponding Trans-lsomer

Ｓｙｎｔｈｅｓｉｓｏｆ（±）－ＤｅｏｘｙｓｃｈｉｓａｎｄｒｉｎａｎｄｔｈｅＣｏｒｒｅｓｐｏｎｄｉｎｇＴｒａｎｓ－ｌｓｏｍｅｒＳｙｎｔｈｅｓｉｓｏｆ（±）－ＤｅｏｘｙｓｃｈｉｓａｎｄｒｉｎａｎｄｔｈｅＣｏｒｒｅｓｐｏｎｄｉｎｇＴｒａｎｓ－ｌｓｏｍｅｒ￥...     

The First and Facile Synthesis of (±) Syringaresinol

The first and facile synthesis of (±)syringaresinol was described.     

Total Synthesis of (±) Euphraticol and Its Analogues

Total syntheses of racemic Euphraticol and its analogues are described, they constitute anew and efficient synthetic route to abietane diterpenoids. The key steps are alkylation of lithium eno-late of 8 with iodides in the presence of HMPA.     

Synthesis of (±)-phthalascidin 622

A synthesis of functionalized phenolic α-amino-alcohols (±)-8 and (±)-16 as synthetic precursors of the catechol tetrahydroisoquinoline structure of phthalascidin 650 was disclosed. (±)-8 was prepared in 5 steps from the commercially available sesamol. Starting from 3-methyl catechol 5, 8 steps gave rise to the synthesis of phenolic α-amino-alcohol (±)-16 in 27% overall yield. This synthetic strategy involved the elaboration of fully functionalized aromatic aldehyde 13 and its transformation into a phenolic α-amino-alcohol (±)-16, through a Knoevenagel condensation, simultaneous reduction of nitroketene and ester functions, and hydrogenolysis of the benzyl protecting group. The pentacycle (±)-4 was obtained after 4 additional steps. The Pictet-Spengler cyclisation between the phenolic α-amino-alcohol (±)-16 and the N-protected α-amino-aldehyde 4 allowed to obtain (1,3′)-bis-tetrahydroisoquinoline 17 with N-methylated and N-Fmoc removed. The last step was a Swern oxidation allowing the expected intramolecular condensation.