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Abstract: Radicamine B 5 was synthesized from p-hydroxy benzaldehyde 7 stereoselectively using acid catalysed amido cyclisation with the help of neighbouring group participation (NGP). Without NGP both radicamine B 5 and its epimer 5-epi radicamine B 6 were obtained. The key steps of the synthesis are Sharpless asymmetric dihydroxylations and acid mediated amido cyclisation. [Copyright &y& Elsevier]

Abstract: The highly stereoselective Grignard addition on chiralimine 8 and opening of chiral epoxide 9 with Grignard reagent have been used as key steps in the stereoselective synthesis of cytotoxic anhydrophytosphingosine pachastrissamine (jaspine B) and N,O,O,O-tetra-acetyl d-lyxo-phytosphingosine. [Copyright &y& Elsevier]

Abstract: A common and stereoselective strategy for the synthesis of N,O,O,O-tetra-acetyl d-ribo-(2S,3S,4R)-phytosphingosine and 2-epi-jaspine B was achieved by using Grignard addition on N-benzyl sugar lactamine and Wittig olefination as key steps. [Copyright &y& Elsevier]

Abstract: A short synthesis of hydroxyethylene dipeptide isostere, a core unit of the HIV-protease inhibitors ritonavir and lopinavir, its C-3 epimer and C 2 symmetric diamino diol is described. The crucial aspects of the synthesis are self-cross metathesis and exploitation of C 2-symmetric of the metathesis product 8 to obtain the required skeleton. [Copyright &y& Elsevier]

Abstract: A novel stereoselective synthesis of N-Boc-(2S,3S)-3-hydroxy-2-phenylpiperidine was achieved from d-mannitol involving the highly stereoselective addition of phenyl Grignard to an allyl imine (de >98%) and ring-closing metathesis (RCM) in the key steps. [Copyright &y& Elsevier]

A novel, stereo selective synthesis of (−)-cytoxazone 1a and stereoselective synthesis of (+)-5-epi-cytoxazone 1b were achieved via stereoselective Grignard addition of vinylmagnesium bromide on N-Boc al ehyde obtained from p-hydroxy-d-phenylglycine 2 followed by cyclization of N-Boc alcohol 6, ozonolysis and reduction to get (+)-5-epi-cytoxazone. Compound 6 underwent mitsunobu conditions, deprotection of ester followed by cyclization of N-Boc alcohol to get (−)-cytoxazone. #IICT Communication Number: 020616. [ABSTRACT FROM AUTHOR]

Abstract: A Chiron approach for the synthesis of (+)-secosyrin 1 from d-mannitol has been described. The key steps are a stereoselective Wittig reaction and an intramolecular Michael addition on the disubstituted butenolide, leading to a highly stereoselective formation of the tertiary chiral centre of (+)-secosyrin 1. [Copyright &y& Elsevier]

Abstract: A common method for the synthesis of 4a-carba-β-l-lyxofuranose and 4a-carba-β-l-arabinofuranose from d-mannose and 2,2,5-trimethyl-3a,6a-dihydro-cyclopenta[1,3]dioxol-4-one from d-ribose is described using catalytic Nozaki-Hiyama-Kishi (NHK) conditions and ring closing metathesis (RCM). In this transformation, ω-deoxy-ω-iodo manno/ribo furanoside undergoes reductive elimination in the presence of Mn/CrCl3 to give the corresponding olefin-aldehyde which was trapped by nucleophile under the same conditions to afford the desired diolefinic species. The ring closing metathesis reaction on these diolefinic species with Grubbs second generation catalyst produced the required carbocycles. [Copyright &y& Elsevier]

Abstract: A new strategy for the synthesis of 1,2-dideoxy iminosugar C-glycosides and indolizidines involving highly stereoselective [2,3]-Wittig rearrangement from Garner aldehyde has been developed. This rearrangement yielded an optically pure, highly functionalized key intermediate, which has been further utilized for the synthesis of 5-epi-ethylfagomine, 2-epi-5-deoxyadenophorine, and 5-hydroxymethyl indolizidine. [Copyright &y& Elsevier]

A versatile and efficient method for the preparation of (2S)-2-(hydroxymethyl)-N-Boc-2,3-dihydro-4-pyridone from l-(−)-phenylalanine 2 utilising the aromatic system as a masked β-keto aldehyde was developed. The key step in the sequence is an intramolecular cyclisation of 6 to give 2,3-dihydropyridin-4-ones. [Copyright &y& Elsevier]