Chirality in gold(III) homodimeric complexes

Vinylgold complex 4 and aurocycle 5 were successively prepared from the protected (S)-2-hydroxymethyl-5-alkynyl-3,4-dihydro-2H-pyrrole using AuCl3. The dimerization of 5 in the presence of K2CO3 gave the chiral homodimers 6a(S,aR) + 6b(S,aS) which exhibited catalytic activity with AgSbF6. Using the X-ray data obtained for 5 and 6a, a transition state explaining the diastereoselectivity (de = 50 at -50 degrees C) was proposed. (C) 2020 Elsevier Ltd. All rights reserved.