Abstract
A golden opportunity: A novel gold-catalyzed oxidative ring-expansion of unactivated cyclopropylalkynes using Ph 2 SO has been developed (see scheme). For substrates bearing a donor group at the cyclopropane ring, preliminary results reveal a distinct cleavage of the cyclopropane unit; such a ring cleavage is further applicable to the synthesis of 2H-pyrans. L=P(tBu) 2 (o-biphenyl), Tf=triflate. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.