Generation and reaction of ammonium ylides in basic two-phase systems

Reaction of the quaternary ammonium salts 2a-i with electrophilic alkenes 3, active alkylating agents 7 or aromatic aldehydes 11, carried out in basic two-phase systems A-D, afforded cyclopropanes 4, cyanoalkenes 8 or cyanooxiranes 12 respectively, via the corresponding ammonium ylides 2(+-). The method is very simple, and gives cyclopropanes 4 and cyanoalkenes 8 in high yield. Under similar conditions, 1-cyanodienes 8aa,ba were cyclopropanated at the gamma,delta-double bond with formation of vinylcyclopropanes 9a,b. The stereochemistry of the prepared cyclopropanes was elucidated from literature, H-1 NMR spectroscopic data, NOE experiments or X-ray single crystal analysis. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).