Veronique Gouverneur

Asymmetric Amination of Carboxylic-acids Via a Diels-alder Strategy

2-azadienes 1 which are readily prepared from acyl chlorides react with high facial selectivity with the chiral carbamoyl nitroso dicnophile 2. Reduction and hydrolysis of the adducts yield enantiomerically pure amino acids.

2-aza-1,3-dienes: Methods of synthesis and stereochemical studies

2-Aza-1,3-dienes bearing an activating trialkylsilyloxy group at C-3 have been prepared via three routes. The first route involves the silylation of N-acylimidates which are readily available from iminoether hydrochlorides and acid chlorides. According to a more general route towards these doubly activated dienes, N-trialkylsilylimidates and N-trialkylsilylimines derived from non-enolizable aldehydes were conveniently converted in a one-pot sequence into the corresponding azadienes by reaction with an acid chloride in the presence of triethylamine. Finally, cyclic dienes could be prepared by direct silylation of glutarimide on both oxygens with trialkylsilyltriflate in the presence of triethylamine. The configuration and conformation of 2-azadienes have been established by H-1, C-13 and N-15 NMR spectroscopy.

Stereoselective Diels-alder Reactions of a New Chiral Carbamoylnitroso Compound

Abstract A new chiral carbamoylnitroso dienophile 1 has been prepared from a substituted pyrrolidine possessing C2 symmetry. Compound 1 reacts with dienes to yield (4 + 2) cycloadducts with very high diastereoisomeric excesses.

Asymmetric Diels-Alder reactions of a nitroso compound derived from D-bornane-10,2-sultam

Abstract Acylnitroso dienophile 3 derived from D-bornane-10,2-sultam undergoes cycloaddition with high yields and complete facial selectivity to cyclopentadiene and cyclohexadiene. When the nitroso group is attached to the sultam nitrogen, it is no longer reactive in Diels-Alder reactions.

A new access to spiro-isozazolines derivatives

Abstract A series of spiro-isoxazolines 1a-e was prepared in an one-step procedure by treating the corresponding tricarbonyl 3a-e derivatives with hydroxylamine hydrochloride.

An improved synthesis of iodohydrins from alkenes

Abstract A series of iodohydrins was prepared in excellent yields in a one-step procedure by treating the corresponding alkenes at −20°C with NIS in a mixture of H2O and DME.

New acylnitroso compounds for the asymmetric oxyamination of dienes

A series of new enantiomerically pure acylnitroso compounds have been prepared and tested as dienophiles for the asymmetric oxyamination of dienes. Very high selectivities were obtained with acylnitroso compounds derived from diphenylmethoxymethyl pyrrolidine 2c, the C-2-symmetric pyrrolidines 2d-e and camphorsultam 2f

A novel access to alicyclic phosphine oxides via ring closing metathesis

Abstract A series of cyclic phosphine oxides 5a-e was prepared in a one-step procedure by RCM of dienes 4a-e . The methodology was extended to the preparation of the bis-phosphine oxide 5f .

Total Synthesis of (±)-Halomon by a Johnson–Claisen Rearrangement

The total synthesis of the polyhalogenated antitumour agent halomon (1) was accomplished with two novel transformations as key steps: a Johnson-Claisen rearrangement of a dichlorinated alkene for the preparation of the tertiary chlorinated C3 and a new rearrangement of bromohydrins for the regiospecific introduction of the bromine and chlorine atoms on C6 and C7, respectively.

Electrophilic amination of 2-azadienes

2-Azadienes 1 bearing a trialkylsilyloxy group on position 3 can be regarded as carboxylic acid synthons. Their cycloadditions with several classes of nitroso compounds have been studied in details as well as the transformation of the adducts into alpha-amino acids. This study showed that arylnitroso compounds such as nitrosobenzene reacted with 2-azadienes to give adducts that are potential precursors of alpha-N-arylamino acids. We have outlined an important limitation to the use of alpha-chloronitroso compounds. They are not compatible with highly functionalized dienes like 2-azadienes. On the other hand alpha-cyanonitroso and acylnitroso compounds reacted with azadienes to give adducts which were readily converted into alpha-amino acid derivatives. Copyright (C) 1996 Elsevier Science Ltd