Stille Cross-Couplings of Unactivated Secondary Alkyl Halides Using Monoorganotin Reagents
摘要:
The first catalyst that achieves Stille cross-couplings of secondary (as well as primary) alkyl halides has been developed. The method employs easily handled and inexpensive catalyst components (NiCl2 and 2,2'-bipyridine) and, through the use of monoorganotin reagents, avoids the formation of toxic and difficult-to-remove triorganotin side products.
Reagents containing carbon–tin–halogen inter-element linkages were effective for palladium-catalyzed carbostannylation. In situ generated allyltin trichlorides add to carbon–carbondoublebonds of bicyclo[2.2.1]hept-2-ene (norbornene) and bicyclo[2.2.1]hepta-2,5-diene (norbornadiene), stereoselectively, under the catalysis of palladium(0) species in good yields. The regioselectivity of unsymmetrically