α‐Chlor‐nitrone II: Eine Methode zur Darstellung von γ‐Lactonen aus Olefinen. Über synthetische Methoden, 6. (vorläufige) Mitteilung

Abstract

The addition products obtained by the Ag+‐induced reaction of α‐chloro‐aldonitrones with olefins (see preceding communication) can be utilized efficiently for making γ‐lactones (see scheme 1).

Synthesis with 1,2-oxazines. 3. Reactions of .alpha.-chloroaldonitrones with enol ethers: a synthetic route to medium-ring lactones

“…Caled for C46H50NO2B: C, 83.45; H, 7.78; N, 2.16. (5) 7V-CycIohexyl-2,3-benz-S,13-dioxa-14-ammonium[5.5.4]propell-14-ene Tetraphenylborate (20c): from 11c in 81% yield; mp 143-182 °C (dec); IR 1665 and 1600 cm-1; NMR 0.9-2.0 (m, 22 H), 2.5-2.S (m, 3 H), 3.6 (m, 2 H), 6.4 (m, 1 H), 6.S-7.5 (m, 24 H). Anal.…”

“…Caled for C23H32NO2: C, 77.80; H, 9.22; N, 8.87. (5) IV-Cyclohexylimino-Á7'íS-ethano-3,4,5,6,7,9,10-hexahydro-8íf-2-benzoxacyclododecan-1 -one (22c): from 20c. Propellane 21c (290 mg) (0.78 mmol; 78% yield) was isolated: IR (neat) 1670 and 1590 cm-1.…”

“…After achieving the first objectives-construction of propellanes 14,12 7, and 1 la-c-we came to the last aspect of this work: synthesis and thermal cycloreversion of enamines 17a,b and 2la-c applying reaction conditions already worked out by Eschenmoser et al 5 to the solid tetraphenylborate imminium salts 16a,b and 20a-c, respectively. On treating these salts with solid K2CO3 in dichloromethane at 0 °C, deprotonation to the corresponding enamines took place.…”

“…Steric hindrance in achieving a suitable conformation for cycloreversion was considered here as a possible reason for a thermal stability of 17a. Different conformations of the cycloreverting intermediates can explain the appearance of 1:1 E/Z aldimines in 18b and 22a-c. 5 The aldimines were converted to the unsaturated aldehyde lactones in 76% (18b -* 19b) and 65% (22a -* 23) yield using the S1O2/H2O hydrolysis used previously.5 Similarly, 18a was converted to 19a in 70% yield.…”

α‐Chlor‐nitrone I: Darstellung und Ag+‐induzierte Reaktion mit Olefinen. Über synthetische Methoden, 5. (vorläufige) Mitteilung

“…Reaktionsprodukte I11 und IV folgt aus den in Tab. 2 gegebenen analytischen und spektroskopischen Daten, und vor allem auch aus dem Verlauf der in den beiden nachfolgenden Mitteilungen[18] [19] beschriebenen Umsetzungen. Wie das Beispiel mit l-Methyl-l-cyclohexen und auch das in der nachsten Mitteilung [lS] behandelte Verhalten von l-Hexen, Methylen-cydohexan und Cyclopentadien zeigen, entspricht der konstitutionelle Verlauf der Anlagerung der N-…”