Dipolar cycloaddition reaction of diazoalkanes with trimethylsilyl substituted alkynes. Steric control of regiochemistry by the trimethylsilyl group
作者:Albert Padwa、M. Woods Wannamaker
DOI:10.1016/s0040-4020(01)86680-1
日期:1990.1
coefficient with that of the larger dipolarophile LU coefficient. Dipolar cycloaddition of several 2-(trimethylsilyl) substituted alkynes led to the unexpected regioisomer. Regiochemical control can be attributed to steric rather than to stereoelectronic factors when a bulky trimethylsilyl group is attached to the dipolarophile. In certain cases some of the cycloadducts undergo rearrangement to pyrazoles
Preparation and reactivity of arylsulfonyl substituted cyclopropenes
作者:Albert Padwa、M. Woods Wannamaker
DOI:10.1016/s0040-4020(01)86547-9
日期:1991.8
behavior of several arylsulfonyl substituted alkynes with 2-diazopropane has been carried out. These activated acetylenes react to give 3H-pyrazoles which extrude nitrogen on photolysis to produce cyclopropenes in high yield. Soft nucleophiles such as thiophenoxide readily add to the activated pi-bond to give thiophenyl substituted cyclopropanes. Reaction of 1-phenylsulfonyl-2,3,3-trimethylcyclopropene