Synthetic Studies to Lyngbouilloside: A Phosphate Tether-Mediated Synthesis of the Macrolactone Core

A concise synthetic pathway to the originally assigned structure of lyngbouilloside macrolactone (3) is reported. The core macrocycle 3 was synthesized via a phosphate tether-mediated, one-pot, sequential RCM/CM/chemoselective hydrogenation reaction, Roskamp homologation, and a high yielding Boeckman acylketene cyclization

Phosphate Tether-Mediated Approach to the Formal Total Synthesis of (-)-Salicylihalamides A and B

A concise formal synthesis of the cytotoxic macrolides (-)-salicylihalamides A and B is reported. Key features of the synthetic strategy include a chemoselective hydroboration, highly regio- and diastereoselective methyl cuprate addition, Pd-catalyzed formate reduction, and an E-selective ring-closing metathesis to construct the 12-membered macrocycle subunit. Overall, two routes have been developed from a readily prepared bicyclic phosphate (4-steps), a 13-step route and a more efficient 9-step sequence relying on regioselective esterification of a key diol

Phosphate Tether-Mediated Ring-Closing Metathesis Studies to Complex 1,3-anti-Diol-Containing Subunits

This is the peer reviewed version of the following article: Chegondi, R., Maitra, S., Markley, J. L., & Hanson, P. R. (2013). Phosphate Tether-Mediated Ring-Closing Metathesis Studies to Complex 1,3-anti-Diol-Containing Subunits. Chemistry (Weinheim an Der Bergstrasse, Germany), 19(25), 10.1002/chem.201300913. http://doi.org/10.1002/chem.201300913, which has been published in final form at doi.org/10.1002/chem.201300913. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.An array of examples of diastereoselective, phosphate tether-mediated ring-closing metathesis reactions, which highlight the importance of product ring size and substrate stereochemical compatibility, as well as complexity, is reported. Studies focus primarily on the formation of bicyclo[n.3.1]phosphates, involving the coupling of C2-symmetric dienediol subunits with a variety of simple, as well as complex alcohol cross-partners

Multicomponent reactions in PEG-400: ruthenium-catalyzed synthesis of substituted pyrroles

International audienceAn efficient and eco-friendly method for the synthesis of substituted pyrroles has been developed via ruthenium-catalyzed multicomponent reaction of ketone, amine, and ethylene glycol in PEG-400 as solvent medium without using any external ligand. The catalytic system and solvent can be recycled with the same, as well as different, ketones with minimum loss of Ru-catalyst activity

Phosphate Tether-Mediated Ring-Closing Metathesis for the Generation of Medium to Large, P-Stereogenic Bicyclo[n.3.1]phosphates

A phosphate tether-mediated ring-closing metathesis study towards the synthesis of P-stereogenic bicyclo[6.3.1]-, bicyclo[7.3.1]-, and bicyclo[8.3.1]phosphates is reported. This study demonstrates expanded utility of phosphate tether-mediated desymmetrization of C2-symmetric, 1,3-anti-diol dienes in generating complex medium to large, P-stereogenic bicyclo[n.3.1]phosphates.

A Concise, Phosphate-Mediated Approach to the Total Synthesis of (−)-Tetrahydrolipstatin

An efficient synthesis of (−)-tetrahydrolipstatin (THL) is reported. This method takes advantage of a phosphate tether-mediated, one-pot, sequential RCM/CM/hydrogenation protocol to deliver THL in 8 total steps from a readily prepared (S,S)-triene. The strategy incorporates selective cross metathesis, regio-selective hydrogenation, regio- and diastereoselective cuprate addition and Mitsunobu inversion for installation of the C5 formamide ester subunit

A Phosphate Tether-Mediated, One-pot, Sequential RCM/CM/Chemo-selective Hydrogenation Protocol

A versatile three-step, one-pot, sequential reaction protocol involving RCM, CM, and chemoselective hydrogenation is reported. This phosphate tether-mediated process occurs without intermediate isolation, is chemoselective and is governed by stereoelectronic properties innate to phosphate tethers, which ultimately act to preserve the integrity of the bisallylic, bicyclic phosphate for subsequent nucleophilic additions. Overall, this process can be used to efficiently generate advanced polyol synthons

CGMap Ongoing Research in Africa Projects Summary

This summary looks at the number of projects entered in the map, countries where projects are reported to be working and the research area that the projects focus on. Data was extracted on July 06, 2010

Total Synthesis of Dolabelide C: A Phosphate-Mediated Approach

The first synthesis of dolabelide C (1), a cytotoxic marine macrolide, is reported utilizing a phosphate tether-mediated approach. Bicyclic phosphates (S,S,SP)-5 and (R,R,RP)-5 serve as the central building blocks for the construction of two major 1,3-anti-diol subunits in 1 through selective cleavage pathways, regioselective olefin reduction and cross-metathesis. Overall, phosphate-mediated processes provided copious amounts of both major subunits allowing for a detailed RCM macrocyclization study to the 24-membered macrolactone 1

Total synthesis of hyacinthacine A<SUB>1</SUB>, a glycosidase inhibitor

A practical and enantioselective total synthesis of hyacinthacine A<SUB>1</SUB> is achieved involving syn allylic epoxide opening with retention using Pd catalysis and "domino" hydrogenation (five steps in one pot) sequences