Hélène Pellissier

Dialkylation of 2,3-butanedione diketal with 1,8-bis(trimethylsilyl)-2,6-octadiene (BISTRO). Application to the synthesis of estrone derivatives

Abstract Titanium tetrachloride mediated-dialkylation of 2,3-butanedione ketal 2 by 1,8-bis(trimethylsilyl)-2,6-octadiene (BISTRO) 1 led to 1-acetyl-1-methyl-2,5-divinylcyclopentane 4 . This latter was methoxycarbonylated (NaH/dimethylcarbonate) and then alkylated with iodobenzocyclobutene (Cs 2 CO 3 /acetone) to give a benzocyclobutenic intermediate 6 , whose thermolysis provided the 12-oxo-estrane derivatives 8–11 .

Regiochemistry of Wacker-type oxidation of vinyl group in the presence of neighboring oxygen functions. Part 1

Abstract Palladium(II) oxidation of (±)-17α-vinyl-1,3,5(10)-gonatriene derivatives 1 bearing a lactonic bridge on the β-face affords the expected acetyl derivatives. In contrast, when the lactonic bridge or a hydroxy group is present on the α-face (syn relationship), aldehydes resulting from an anti-Markovnikov hydroxypalladation are obtained in appreciable yields.

Regiochemistry of wacker-type oxidation of vinyl group in the presence of neighboring oxygen functions

Abstract Palladium (II) oxidation of (±)-17α-vinyl-1,3,5(10)-estratriene derivatives 1 bearing a lactonic bridge on the β-face affords the expected acetyl derivatives. In contrast, when the lactonic bridge or a hydroxy group is present in the α-face (syn relationship), aldehydes resulting of an anti-Markovnikov hydration are obtained in appreciate yields.

A five step synthesis of (d,l)-estrane derivatives from 1,3-butadiene

Abstract A spirolactone 2 , obtained in two steps from 1,3-butadiene (ca. 50 %), was methoxycarbonylated (LiHMDS / dimethylcarbonate) and alkylated with iodo

SYNTHESIS OF 18,18-DIFLUORO- OR 18,18,18-TRIFLUORO-3-METHOXY-12-OXAESTRA-1,3,5(10)-TRIENES

Abstract Titanium tetrachloride mediated dialkylation of acetic anhydride, trifluoroacetic anhydride or difluorochloroacetic anhydride by 1,8-bis(trimethylsilyl)-2,6-octadiene (BISTRO) leads, respectively, to dl -1-methyl-2,5-divinylcyclopentan-1-ol, dl -1-difluoromethyl-2,5-divinylcyclopentan-1-ol or dl -1-trifluoromethyl-2,5-divinylcyclopentan-1-ol. Esterification of these compounds with 4-methoxybenzocyclobutene-1-carboxylic acid and then pyrolysis led to 3-methoxy-12-oxa-17-vinylestra-1,3,5(10)-trien-11-one and to corresponding 18,18-difluoro or 18,18,18-trifluoro derivatives. Further transformations give rise to 3-methoxy-12-oxa-17-(2-oxoethyl)-18,18-difluoroestra-1,3,5(10)-trien-11-one and to the corresponding 18,18,18-trifluoro derivative.

Preparation of trifluoromethyl-substituted alcohols from allylsilanes and trifluoroacetic anhydride

Abstract The titanium tetrachloride-mediated addition of allyltrimethylsilane or 1,8-bis(trimethylsilyl)-2,6-octadiene and trifluoroacetic anhydride led to trifluoromethyl-diallylcarbinol or ( dl )-1-trifluoromethyl-2,5-divinylcyclopentanol, respectively, in fair yields; this latter was further converted into several 1-trifluoromethyl-2-vinylcyclopentane derivatives.

CHEMICAL AND BIOCHEMICAL HYDROXYLATIONS OF STEROIDS. A REVIEW

INTRODUCTION ................................................................................................................................. 3 I . CHEMICAL HYDROXYLATION OF STEROIDS .................................................................... 3 I . Hydroxylation by Photochemical Process andlor Iodine Derivatives ................................. 2 . Hydroxylation with Dioxiranes and Oxaziridines ......................................................................... 9 3 . Hydroxylation with Ozone ........................................................................................................... 12 4 . Oxidation at Activated Carbon ..................................................................................................... 12 ..................................... 16 6 . A-ring Hydroxylation with Chromic and Mercury Derivatives .................................................. 17 7 . A-ring Hydroxylation vio Xanthylium Salts ................................................................................ 18 8 . Hydroxylation in Superacids ........................................................................................................ 19 9 . Other Hydroxylation Methods ...................................................................................................... 20 I0 . Catalytic Hydroxylations by Metal Porphyrins .......................................................................... 22 I1 . BIOCHEMICAL HYDROXYLATION OF STEROIDS .......................................................... 24 1 . Introduction ......................... .................................................................................... 24 2 . Monohydroxylations ..................................................................................................................... 25 a . C-1 Hvdroxylation .......................................................... b . C-2 Hydroqdation ................................................................................................................... 25 c . C-3 Hylroqlation .................................................................................................................... 26 d . C-4 Hvdro.xvlation ................................................................................................................... 26 e . C-6 Hjdroqlution .. .................................................................................... 21 f . C7 Hydroqlrrtion .................................................................................................................... 29 g . C-8 Hydroxylation ................................................. ............................................................. 31 h . C-9 Hydroxylaticin ................................................. ............................................................. 31 i . C10 Hydro.tylation .................................................................................................................. 33 j . CI I Hydro.r

Reactions of isocyanides. II- addition to acetals

ation ..................................... ............................................................ 33 5 . Hydroxylation with Chromic Anhydride ..................

Stereoselective synthesis of (8β, 14α)-11-methoxycarbonyl-13β-(p-bromophenyl)-17-acetylgona-1,3,5(10)-trienes

In the presence of TiCl4, tert-butyl isocyanide reacts with aldehyde acetals to afford β-alkoxycyanoenamines.

Synthèse asymétrique assistée par ligandes. I. modélisation d'auxiliaires chiraux pour la réaction de diels-alder enantiosélective.

Abstract Titanium tetrachloride mediated dialkylation of methyl 4- p -bromophenyl-4-oxobutanoate ethylene ketals 2 by 1,8-bis(trimethylsilyl)-2,6-octadiene 1 (BISTRO) led to a mixture of methyl dl and meso -3-(1- p -bromophenyl-2,5-divinylcyclopentan-1-yl)-propanoates 3 . Iodolactonisation, reduction with Bu 3 SnH, Jones oxidation, methoxycarbonylation, alkylation by iodobenzocyclobutene, demethoxycarbonylation and then pyrolysis led to the title compounds.