Joan-Carles Fernàndez

Synthesis of enantiopure (2R,3aS,7aS)-2-ethyloctahydroindol-6-one and its fischer indolization

Abstract A diastereoselective synthesis of (−)-2-ethyloctahydroindol-6-one 12 starting from O- methyl- L -tyrosine 1 is described. The process first involves the synthesis of enantiopure (−)-1-(4-methoxyphenyl)-2-butylamine 8 , which, after Birch reduction, N -benzylation and acid treatment, renders the cis -fused azabicyclo 12 . Studies on the Fischer indolization of 12 are also reported.

BAL resin for the preparation of secondary amines

Although amino acids anchored through the amino function to BAL resins can not easily be released from the resin by treatment with neat trifluoroacetic acid, we have shown that secondary amines can be obtained from BAL resins using trifluoroacetic acid solutions.

A straightforward route to ibophyllidine alkaloids by a double transannular cyclization

Ring cleavage of indolo[2,3-a]quinolizidine 4 to an octahydroazecino[5, 4-b]indole system, followed by introduction of a cyano substituent and double transannular cyclization gives (±)-deethylibophyllidine.

Synthesis of 7-azabicyclo[2.2.1]heptanes by anionic cyclization

Cyclizations of α-amino-organolithiums, derived by tin-lithium exchange, which proceed via a stereoselective two-electron process and totally regiospecific 5-exo-trig ring closure, have been extended to the preparation of the 7-azabicyclo[2.2.1]heptane ring system. Cyclization occurs from either the cis or the trans isomer of 5-allyl-2-tri-n-butylstannyl-N-benzylpyrrolidine to give only the exo product as a single diastereomer in isolated yields up to 83%.

Synthesis of 4-ethyloctahydroindolo[2,3-a]quinolizine-2-carbaldehydes

Abstract The isomerization-cyclization of tetrahydropyridine 7 by AcOH leads to 4-ethyloctahydroindolo[2,3-a]quinolizine-2-carbaldehydes (8). When the process is carried out with aqueous AcOH, indolizidinoindole 9 is formed as a by-product in a competitive way. Compound 7 is available via reductive cyanation of pyridinium salt 1 followed by treatment of nitrile 2 with ethylmagnesium bromide.

A new stereoselective approach to the manzamine alkaloids

The key step in a new, stereoselective approach to the manzamine alkaloids involves an intramolecular azomethine ylide cycloaddition reaction, which forms rings B and C simultaneously, together with three new chiral centres; this has allowed a rapid access to the core ABC ring system of manzamine A.