Synthesis of (3R,5R)-harzialactone A and its (3R,5S)-isomer

• Gowravaram Sabitha,
• Rangavajjula Srinivas,
• Sukant K. Das and
• Jhillu S. Yadav

Beilstein J. Org. Chem. 2010, 6, No. 8, doi:10.3762/bjoc.6.8

• carbon in the downfield region (100.5 ppm) [7]. In conclusion, a stereoselective synthesis of natural (+)-(3R,5R)-harzialactone A and its nonnatural stereoisomer (3R,5S) has been accomplished. Natural harzialactone A (1), and its (3R,5S)-isomer (2). Retrosynthesis of harzialactone A (1). Synthesis of

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• the indole moiety, this method led to a convenient stereoselective synthesis of a highly substituted pyrroloindole framework 74 (Scheme 30); however, equimolar amounts of triethylborane were necessary. An improved FC allylation of indoles with allyl alcohols was developed recently by Breit et al

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• (in the case of transition metal-catalyzed reactions) also can be problematic in large-scale syntheses, especially in pharmaceutical applications. Consequently, reactions based on the use of supported catalysts are in many ways a more attractive option for the stereoselective synthesis of chiral

• was developed for the reaction of imino esters with ketenes, leading to the stereoselective synthesis of ß-lactams [30]. Ketene was generated from the corresponding acid chloride with polymer-supported BEMP 17, and was reacted with an imino ester in a reaction catalyzed by the resin-supported quinine

A short stereoselective synthesis of (+)-(6R,2′S)-cryptocaryalactone via ring- closing metathesis

• Palakodety Radha Krishna,
• Krishnarao Lopinti and
• K. L. N. Reddy

Beilstein J. Org. Chem. 2009, 5, No. 14, doi:10.3762/bjoc.5.14

• short stereoselective synthesis of (+)-(6R,2′S)-cryptocaryalactone was successfully completed. Key steps included the application of Carreira’s asymmetric alkynylation reaction to form a propargylic alcohol and subsequently lactone formation using the powerful ring-closing metathesis reaction. Keywords

• ]. Its absolute stereochemistry was established by H. H. Meyer through stereoselective synthesis [25]. Recently Yadav et al. have synthesized (6R,2′S)-cryptocaryalactone and its epimer using stereoselective reduction of δ-hydroxy-β-keto ester [33]. All other possible isomers of cryptocaryalactone were

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Asymmetric synthesis of biaryl atropisomers by dynamic resolution on condensation of biaryl aldehydes with (−)-ephedrine or a proline- derived diamine

• Ann Bracegirdle,
• Jonathan Clayden and
• Lai Wah Lai

Beilstein J. Org. Chem. 2008, 4, No. 47, doi:10.3762/bjoc.4.47

• ][8][9]. In view of the thermal instability inherent in a stereogenic bond (rather than a centre) dynamic methods appear particularly suited to the stereoselective synthesis of atropisomers [10][11]. In connection with our work on non-biaryl atropisomers such as amides [12][13][14][15][16], ethers [17

Understanding the mechanism of Pd-catalyzed allylic substitution of the cyclic difluorinated carbonates

• Jun Xu,
• Xiao-Long Qiu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2008, 4, No. 18, doi:10.3762/bjoc.4.18

• prepare potential bioactive fluorinated nucleosides, our group recently described the stereoselective synthesis of 3',3'-difluoro-4',5'-unsaturated OTCs 2–3 and 5 [11]. The whole synthesis highlighted the stereoselective Reformatskii-Claisen rearrangement, ring-closing metathesis (RCM), and Pd-catalyzed

Stereoselective synthesis of (2S,3S,4Z)-4-fluoro- 1,3-dihydroxy- 2-(octadecanoylamino)octadec- 4-ene, [(Z)-4-fluoroceramide], and its phase behavior at the air/water interface

• Gergana S. Nikolova and
• Günter Haufe

Beilstein J. Org. Chem. 2008, 4, No. 12, doi:10.3762/bjoc.4.12

• diastereomeric 4-fluoro-4,5-dihydroceramides, which we synthesized recently [28]. We became interested in studying the properties and report in this paper the stereoselective synthesis of (Z)-2-amino-4-fluorooctadec-4-ene-1,3-diol (4-fluorosphingosine, 1b) and (Z)-2-octadecanoylamino-4-fluorooctadec-4-ene-1,3

Knorr- Rabe partial reduction of pyrroles: Application to the synthesis of indolizidine alkaloids

• Brendon S. Gourlay,
• John H. Ryan and
• Jason A. Smith

Beilstein J. Org. Chem. 2008, 4, No. 3, doi:10.1186/1860-5397-4-3

• -alkylindolizidines and the stereoselectivity obtained is opposite to that of catalytic hydrogenation. Conclusion An efficient stereoselective synthesis of indolizidine alkaloids has been developed from α-ketopyrrole intermediates using a modified version of Knorr and Rabe's pyrrole reduction. Background The Birch

A divergent asymmetric approach to aza-spiropyran derivative and (1S,8aR)-1-hydroxyindolizidine

• Jian-Feng Zheng,
• Wen Chen,
• Su-Yu Huang,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2007, 3, No. 41, doi:10.1186/1860-5397-3-41

• . Stereoselective synthesis of (1S,8aR)-1-hydroxyindolizidine (ent-3). One-pot synthesis of ent-3 from amino alcohol 8. Supporting Information Supporting Information File 94: Experimental. Experimental procedures for the synthesis of all compounds described, and characterization data for the synthesized compounds

Single and double stereoselective fluorination of (E)-allylsilanes

• Marcin Sawicki,
• Angela Kwok,
• Matthew Tredwell and
• Véronique Gouverneur

Beilstein J. Org. Chem. 2007, 3, No. 34, doi:10.1186/1860-5397-3-34

• highly efficient and stereoselective synthesis of alkenes featuring bis-allylic stereocentres, one of them being fluorinated, emerged from this study. Significantly, alkenes flanked by two allylic fluorinated stereogenic centres are also accessible upon double electrophilic fluorination of (E

Pd-catalysed [3 + 3] annelations in the stereoselective synthesis of indolizidines

• Olivier Y. Provoost,
• Andrew J. Hazelwood and
• Joseph P. A. Harrity

Beilstein J. Org. Chem. 2007, 3, No. 8, doi:10.1186/1860-5397-3-8

Reaction of benzoxasilocines with aromatic aldehydes: Synthesis of homopterocarpans

• Míriam Álvarez-Corral,
• Cristóbal López-Sánchez,
• Leticia Jiménez-González,
• Antonio Rosales,
• Manuel Muñoz-Dorado and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2007, 3, No. 5, doi:10.1186/1860-5397-3-5

• of allylation reactions, [1] which has been used for the formation of carbo- and heterocycles. [2][3] We have applied it to the stereoselective synthesis of dihydrobenzofurans by means of the condensation of benzoxasilepines with aromatic aldehydes in the presence of Lewis acids. [4][5] Using this

The oxanorbornene approach to 3-hydroxy, 3,4-dihydroxy and 3,4,5-trihydroxy derivatives of 2-aminocyclohexanecarboxylic acid

• Ishmael B. Masesane,
• Andrei S. Batsanov,
• Judith A. K. Howard,
• Raju Mondal and
• Patrick G. Steel

Beilstein J. Org. Chem. 2006, 2, No. 9, doi:10.1186/1860-5397-2-9

• oxanorbornene adduct derived from the Diels-Alder reaction of ethyl (E)-3-nitroacrylate and furan provides a versatile template for the stereoselective synthesis of hydroxylated derivatives of 2-aminocyclohexanecarboxylic acid (ACHC). Introduction In recent years there has been a surge of interest in cyclic β

• describe the stereoselective synthesis of further novel hydroxylated derivatives of ACHC using the exo nitro oxanorbornene adduct as the template. The basis of our approach to these poly hydroxylated cyclohexane β-amino acids was the recognition that the bicyclic oxanorbornene cycloadduct, derived from the

Synthesis of 2,6-trans- disubstituted 5,6-dihydropyrans from (Z)-1,5-syn-endiols

• Eric M. Flamme and
• William R. Roush

Beilstein J. Org. Chem. 2005, 1, No. 7, doi:10.1186/1860-5397-1-7

• -dihydropyrans. Furthermore, there are only limited reports describing the stereoselective synthesis of related tetrahydropyrans through cyclodehydration of enantiopure 1,5-diols substrates.[17] The challenge of synthesizing dihydropyrans 3 or ent-3 from 1,5-diols such as 2 lies in the differentiation of the two