“…The "two-to-two" type cyclization to (S,S,S,S)-10, (R,R,R,R)-11, and (S,S,S,S)-12 was carried out by forming the disodium salts of the diols (S,S)-16 20 and (R,R)-17, 21 respectively with sodium hydride in THF followed by the addition of the ditosylates 18 or 19. The template effect of the sodium ion 11 allowed access to the macrocyclic compounds in yields of 19, 22, and 18% for (S,S,S,S)-10, (R,R,R,R)-11 and (S,S,S,S)-12, respectively.…”