ether (3 X 30 mL). The organic extracts were washed several times with water, dried (MgS04), evaporated to about 5 mL, and passed through 15 g of neutral alumina (Activity II). The desired sweet smelling product eluted with petroleum ether, following elution of diphenyl sulfide, and the combined fractions gave 45 mg (26%) of a colorless oil. It contained about 15% of an impurity which was removed by repeated preparative GC. The colorless oily ketone 14 (>99% pure) had the following: UV (isopentane) e™/ = 29; CD (isopentane) €™ = 0.91, AeJjo = 1.17 (corrected to 100% ee); IR (film)
a = [2+Pb(N03)+]+ b = [2+Pb2+]+ c = [2+Pb(N03)+-C,H50]+ New C-pivot lariat 16-crown-5 ethers and two metal-crown ether complexes are synthesized and characterised by single-crystal X-ray diffraction which indicates that both the crown ring and the side arm are involved cooperatively with the cation (Na+ or Pb2+) in three-dimensional complexation.
In the crystal (space group P2,; Z=2) of [3.3]metacyclophane (V), the molecule assumes a syn geometry with the bridging chains in the chair‐chair conformation as shown.
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