N.m.r. evidence for the existence of P₄S₈

Ein neues Phosphorsulfid mit Adamantangerüst: δ-P4S7

“…In der Reihe der Phosphorsulfide mit Adamantangeru È st gibt es fu È nf mo È gliche Verbindungen, von denen drei bekannt sind: na È mlich P 4 S 10 [1], a-P 4 S 9 1) [2,3] und a-P 4 S 8 [4]. Von P 4 S 10 [5] und a-P 4 S 9 [6] sind Kristallstrukturen bestimmt worden, wa È hrend die Charakterisierung von a-P 4 S 8 ausschlieûlich mit Hilfe der 31 P-NMR-Spektroskopie in Lo È sung erfolgte.…”

The hydroboration of enamines

“…(8) In 1970, Gore and Barieux 7 reported, in the first of a series of six papers, that the hydroboration of the pyrrolidine enamine of dihydrotestosterone 17 with diborane in THF followed by treatment of the intermediate organoborane with refluxing methanol afforded an 80-85% yield of an 82:18 mixture of the isomeric aminosteroids 18a and 18b (Equation 9). (9) In the following year, Barieux and Gore reported a 1,2-carbonyl transposition sequence in which the hydroboration/oxidation of an enamine to the corresponding trans-2-aminoalcohol was a key step (Equation 10). [8][9][10] (10)…”

“…(9) In the following year, Barieux and Gore reported a 1,2-carbonyl transposition sequence in which the hydroboration/oxidation of an enamine to the corresponding trans-2-aminoalcohol was a key step (Equation 10). [8][9][10] (10)…”

Isomérisation cis‐trans en Série Alkyl‐4‐vinyl‐3‐pipéridine par Sigmatropie [3.3]. Synthèse des Epivinyl Isomères des Alcaloïdes du Quinquina

“…a = position axiale; e = position equatoriale.Lettres majuscules pour les couplages ' J et minuscules pour Ies couplages a Iongue distance.Cette position est confirmbe par la disparition de l'effet y de ce substituant qui blinde les atomes C(5) et C(7) de l'isomere cis. Malheureusement les couplages J(3,4) qui confirmeraient la position kquatoriale du substituant CH2COOEt ne sont pas mesurables. b) Isomirisation de 10 en absence de formaldehyde.…”