Roland Remuson

Asymmetric synthesis of quinolizidine alkaloids (−)-lasubine I, (−)-lasubine II and (+)-subcosine II

Abstract The enantioselective synthesis of (−)-lasubine I 1 and the first asymmetric synthesis of (−)-lasubine II 2 and (+)-subcosine II 3 is described. The key step is the intramolecular cyclization of N-acyliminium ion 4 which is derived from (S)-aminoester 6.

Enantioselective synthesis of (−)-indolizidine 167B

Abstract The enantioselective total synthesis of (−)-indolizidine 167B is described. The key step is the intramolecular cyclization of the chiral N -acyliminium ion 6 . Indolizidine 167B was obtained in 7 steps and 17% yield from ethyl ( R )-3-aminohexanoate, with an enantiomeric excess of 93%.

Diastereoselective cyclization of allylsilanes on α-acyliminium ions. A new approach to (±)-myrtine and (±)-epimyrtine

Abstract Total synthesis of (±)-myrtine and (±) epimyrtine is described using an intromolecular allylsi1ane N acyliminium ion cyclization.

ENANTIOSELECTIVE SYNTHESIS OF THE QUINOLIZIDINE ALKALOIDS (+)-MYRTINE AND (-)-EPIMYRTINE

Abstract The enantioselective synthesis of (+)-myrtine 1 and (−)-epimyrtine 2 is described starting from ( S )-2-(2-hydroxypropyl)allyltrimethylsilane 4 using an intramolecular allylsilane N -acyliminium ion cyclization.

A convenient allylsilane-N-acyliminium route toward indolizidine and quinolizidine alkaloids

This review relates all the results that we obtained in the field of the total synthesis of indolizidine and quinolizidine alkaloids using a strategy of the addition of an allylsilane on an N-acyliminium ion. In this paper, we describe the synthesis of racemic indolizidine 167B and chiral indolizidines: (-)-indolizidines 167B, 195B, 223AB, (+)-monomorine, (-)-(3R,5S,8aS)-3-butyl-5-propylindolizidine and (-)-dendroprimine. Next, we relate the synthesis that we have developed in the quinolizidines field: (±)-myrtine and epimyrtine, (±)-lasubines I and II and chiral quinolizidines: (+)-myrtine, (-)-epimyrtine, (-)-lasubines I and II and (+)-subcosine II.

A convenient allylsilane-N-acyliminium route toward 5-alkylindolizidines. Diastereoselective synthesis of (±)-indolizidine 167B

Abstract A highly diastereoselective synthesis of 5-alkylindolizidines is described via an intermolecular addition of the allylsilyl functional group of homoallylic alcohols with an N -acyliminium ion derived from pyrrolidin-2-one.

Enantioselective synthesis of 5-substituted pipecolic acids using an intramolecular allylsilane-iminium ion cyclization

Abstract The application of the intramolecular allylsilane-iminium ion cyclization reaction for the enantioselective synthesis of piperidine derivatives is described. The synthetic potential of this methodology is demonstrated by the enantioselective synthesis of 5-substituted pipecolic acids.

A facile enantioselective synthesis of 2-(2-aminoethyl)allylsilanes, new synthons for piperidine synthesis

Abstract The synthesis of chiral (2-substituted-2-aminoethyl)allylsilanes by cerium mediated trimethylsilylmethylmagnesium chloride addition to the ester group of non racemic chiral β-aminoesters is described.

Microbial synthesis of (+)-(3R)-ethyl 3-hydroxy-3-(3,4-dimethoxyphenyl)propionate

Abstract From the microbiological reduction of ethyl 3-oxo-3-(3,4-dimethoxyphenyl)-propionate, (+)-(3R)-ethyl 3-hydroxy-3-(3,4-dimethoxyphenyl)propionate was prepared on a quantitative scale. The absolute configuration was assigned by X-ray structural determination of the crystallized camphanate derivative.

Enantioselective synthesis of 2-(2-hydroxyethyl)allylsilanes from chiral β-hydroxyesters

Abstract The synthesis of chiral (2-substituted-2-hydroxyethyl)allylsilanes by cerium mediated trimethylsilylmethylmagnesium chloride addition on chiral β-hydroxyesters is described.