Rhodium-catalyzed formation of stereocontrolled trisubstituted alkenes from Baylis-Hillman adducts.

Efficient and general conditions for the formation of stereodefined trisubstituted alkenes by using the rhodium-catalyzed reaction of unactivated Baylis-Hillman adducts with either organoboronic acids or potassium trifluoro(organo)borates are reported (see scheme).We report here efficient and general conditions for the formation of stereodefined trisubstituted alkenes using the rhodium-catalyzed reaction of unactivated Baylis-Hillman adducts with either organoboronic acids and potassium trifluoro(organo)borates. The use of the [{Rh(cod)OH}(2)] precursor gave very fast coupling reactions under low catalyst loading, very mild reaction conditions (from room temperature up to 50 degrees C) and without the need of additional phosphane ligands.

Access to enantioenriched alpha-amino esters via rhodium-catalyzed 1,4-addition/enantioselective protonation.

Conjugate addition of potassium trifluoro(organo)borates 2 to dehydroalanine derivatives 1, mediated by a chiral rhodium catalyst and in situ enantioselective protonation, afforded straightforward access to a variety of protected alpha-amino esters 3 with high yields and enantiomeric excesses up to 95%. Among the tested chiral ligands and proton sources, Binap, in combination with guaiacol (2-methoxyphenol), an inexpensive and nontoxic phenol, afforded the highest asymmetric inductions. Organostannanes have also shown to participate in this reaction.

Baylis-Hillman adducts in rhodium-catalyzed 1,4-additions: unusual reactivity.

In the presence of a rhodium catalyst, unactivated Baylis-Hillman adducts reacted with arylboronic acids to afford trisubstituted alkenes with good yields. This highly efficient reaction (aerobic conditions, low temperature) is believed to proceeds via an unexpected mechanism involving 1,4-addition/beta-hydroxy elimination steps and not pi-allyl type rhodium intermediates.

[Limits of laparoscopic surgery of adrenal glands. Apropos of 17 cases and a review of the literature].

Objectives: To review own cases of laparoscopic adrenalectomy in order to better ascertain limits therapeutic management and indications, compared with the literature data.

Patients-methods: Medical files of 15 patients after 17 laparoscopic adrenalectomies in the Dupuytren hospital of Limoges from February 1994 to November 1996, were analyzed 10 women and 5 men mean aged 59.4 years (22-77) were operated.

[Oculomotor nerve paralysis secondary to dural carotido-cavernous sinus fistula].

Carotid-cavernous sinus fistulas are an uncommon cause of oculomotor nerve palsies. These fistulas are fed by meningeal branches of the internal carotid and/or external carotid arteries. They occur spontaneously, and have symptoms less severe than those of direct carotid-cavernous sinus fistulas.