D A. Evans The Shapiro Reaction -1 Chem 206 Deprotonation of the monoanion occurs predominantly at the kinetically more acidic site giving after elimination the less substituted alkene produc N2 BuLi 2. Quench TrisH、 TMEDAhexane General reviews. Trost, Ed, Comprehensive Organic Synthesis 1992, Vol 6, Chapters 4.3 92, Vol 6, Chapters 4.6. (E(z)=4:1 Shapiro, Organic Reactions 1976, Vol 23, pp 405-507 Mechanism In THF solution regiochemical ratios generally reflect the starting SOaR hydrazone geometries Bond J. Org. Chem. 1978. 43, 154 bUli bUli H 1. TSNHNH2 Grieco J. Org. Chem. 1977. 42, 1717 NR- Side Reaction Li bUlI. THF NHTS propylsulfony! (Trisyl) group is use (Roberts Tet. Let. 1981, 22, 4895 Trisyl Nemoto et al JCS. Perkin Trans. 1 1985. 927. 1. TSNHNH2 O 1.TsNHNH Regiochemistry 2. MeLi, Et0 1. TSNHNH2 via trianion 98% (2%) 2. MeLi, Et,O 1. TsNHNH2 2. LDA (5%nBuLi nBuLi nBuLi R R’ N NHTs R R’ BuLi Me O Me Me Me Me Me O Me Me O Me H Me Me H O O N NHTs N N Li SO2Ar N N Li Li MeO NNHTs Me H Me C5H11 N TrisHN O O Me Me Me CO2Et O S O O NR H Li S NR O O Me Me Me SO2 Me Me Me N N Li SO2Ar Li THF BuLi EtO2C Me Me Me O O Me Me O H Me Me H Me O C5H11 Li Li C5H11 H Me MeO CO2Et Me Me C5H11 Li General Reviews: Trost, Ed., Comprehensive Organic Synthesis 1992, Vol 6, Chapters 4.3 . Shapiro, Organic Reactions 1976, Vol 23, pp 405-507. Trost, Ed., Comprehensive Organic Synthesis 1992, Vol 6, Chapters 4.6. the Triisopropylsulfonyl (Trisyl) group is used (Roberts Tet. Let. 1981, 22, 4895). Trisyl = (95 %) (5 %) 1. TsNHNH2 2. LDA via trianion via dianion 2. LDA 1. TsNHNH2 2. K2CO3 , D 1. TsNHNH2 Bond J. Org. Chem. 1978, 43, 154. In THF solution regiochemical ratios generally reflect the starting hydrazone geometries Grieco J. Org. Chem. 1977, 42, 1717. Nemoto et. al. JCS, Perkin Trans. 1 1985, 927. 80 % nBuLi, THF 65 % 2. LDA 1. TsNHNH2 Deprotonation of the monoanion occurs predominantly at the kinetically more acidic site giving after elimination the less substituted alkene product. (100 %) 1. TsNHNH2 2. MeLi, Et2O (98 %) (2 %) + 2. MeLi, Et2O 1. TsNHNH2 Regiochemistry –TsLi Mechanism: + N2 2. Quench 1. Strong Base D. A. Evans The Shapiro Reaction-1 Chem 206 (E):(Z) = 4:1 TMEDA/hexane + 4 : 1 Side Reaction