Science of Synthesis

Terada, M., Science of Synthesis: Stereoselective Synthesis, (2011) 3, 335.

Enamides and enecarbamates have been used as nucleophiles in the enantioselective intermolecular ene reaction.[‌82‌] For example, the copper-catalyzed aza-ene reaction of α-imino esters ‌55‌ with enecarbamates ‌56‌, using 10 mol% of the copper(II) complex generated in situ from copper(II) trifluoromethanesulfonate and 1,2-diamines ‌57‌, gives the enantioenriched β-amino imines ‌58‌ (‌Scheme 23‌).[‌81‌] This process is applicable to a wide range of enecarbamates, including trisubstituted enecarbamates, which afford diastereomeric mixtures favoring the syn-isomer irrespective of the E/Z geometry of the enecarbamate. However, the yield and the degree of stereoselectivity are dependent on the geometry of the enecarbamate employed, with the E-isomer providing superior results compared to the corresponding Z-isomer. The β-amino imines ‌58‌ obtained can be readily transformed into α,γ-diamino acid derivatives via nucleophilic addition to the resulting imine. Alternatively, hydrolysis under acidic conditions affords the corresponding γ-oxo esters ‌59‌. Furthermore, the enantioselective imino-ene reaction using an N-acyl-α-imino phosphonate as an enophile[‌101‌] has been reported, which provides an efficient method for the construction of α-amino phosphonates in a highly enantioselective manner.

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‌Meeeeeeeeee 88‌

e Meeeeeeeee eeeee eeeeeeeeee ee ‌88‌ ee eeee ‌88‌.

e Meeeeeeeee eee eee eeeee eeeeeeeeeeee.

e ee (eee/eeee) 88:88.

e ee (eee/eeee) 88:88.

Me eeeeeeeee eeeee, eee eeeeee eeeeeeeeeeeeeeee eeeee-eee eeeeeeee ee eeeeeeeeeee eeeeeee eee eeeeeeeee eeeeeeeeeeeee eee eeee eeeeeeeeeeee eeeee α-eeeee eeeeee eee eeeeeee eeeeeeeee eeeee eeee e eeeeeee-eeeeeee eeee eee eeeee eeeeeeee. Meeee ee eee eeeee eeeeeeeeeeeeeeee eeeee-eee eeeeeeee ee eeeeee eeeeeee e eeeeeeeeeeee eeee ee eee α-eeeeeeee,[‌888‌] eee eeeeeeeee ee eeee eeeeeee eee eeeeeeeee eee eeeeeeeee eeee eeeeeeeeeeeeeeeeee. Meee, eeeeeeeee ee M-eeeeeeeeeeeee ‌88‌ eeeeeee eeee eeeeeeee eeeeeeeee eeee eeeeee (8-eeeeeeeeeee)eeeeeeeee, ee eee eeeeeeee ee eeeeee eeeeeeeeee eeee ‌88‌, eeeeeeee eee eeeeeeeeeeeeeee β-eeeee eeeeee ‌88‌ ee eeee eeeee (‌Meeeee 88‌). Me ee eeeeeeeeee eeee eee eeeeeeee eeeeeee eee ee eeeeeeeeeeeee eeeeeee (8.8 eee%), eeeeeeeeeeee eee eeeeeeeeee ee eee eeeeeeeeee eeee eeeeeeee.[‌888‌] Meeeeeeeee ee β-eeeee eeeeee ‌88‌ eeeee eeeeee eeeeeeeeee eeeee β-eeeee eeeeeee ‌88‌. Me eeeeeeee, eee eeeee-eee eeeeeeee eee eeee eeeeeeee ee e eeeeeee eeeeeeee ee eeeee M-eeeeeeeeee eeeee eeee 8 eeeeeeeeeee ee ee eeeeeeee-eeeeeee eeeeeeeeeeee ee eeeeeee eeeeeeeeee eeeeeeeeeee ee e eeeeee eeeeeeeeeeeeeee eeeeee.[‌888‌]

‌Meeeee 88‌ Meeeeeeeeeeeeeee Mee-Mee Meeeeeee ee M-Meeeeeeeeeeee eeee ee Meeeeeeeeeee Meeeeeeee ee e Meeeee Meeeeeeeee Meee[‌888‌]

‌Meeeeeeeeee 88‌

e Meeeeeeeee eeeee eeeeeeeeee ee ‌88‌ ee eeee ‌88‌.

e Meeeeeee eeeeeeeee eeee 8.8 eee% ee ‌88‌.

Meeeeeeeeeee Meeeeeeee

α-Meeee γ-Mee Meeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

Me(MMe)8 (8.8 ee, 8.888 eeee) eee eeeee eee 8 e eeeee eeeeee ee 888 °M. Meeeee ‌88‌ (Me8 = 8-eeeeeeee; 88.8 ee, 8.888 eeee) eee eeeee eeeee ee eeeee eeeeeeeeee eeeeeeee ee MM8Me8 (8.8 eM). Mee eeeee eeee eeee eee eeeeeee eee eeee 8 e eeeee eee eeeee eeeeeee ee eeee eeeee. MM8Me8 (8.8 eM) eee eeee eeeee, eee eee eeee eee eeeeee ee 8 °M. Meeeeeeeeeee ‌88‌ (8.888 eeee) ee MM8Me8 (8.8 eM) eee eeeee ee eeee eeeeeee, eeeeeeee ee α-eeeee eeeee ‌88‌ (8.888 eeee) ee MM8Me8 (8.8 eM) (eeeee eee eeeee eeeeee eeee 88 eee), eee eee eeeeeeeee eeeeeee eee eeeeeee ee 8 °M eee 88 eee. Mee eeeeeeee eee eeeeeeee ee eeeeeeee ee eee. ee MeMMM8, eee eee eeeeeeeee eeeeeee eee eeeeeee ee eeee ee ee eeee eeeeeee eeeeeeee eeeee eee eeeee ee eee eeeeeee eeeee eeeeeee ee eeee. Mee eeeeeee eee eeee eeeeeeeee eeee MM8Me8, eee eee eeeeeee eeeee eee eeeeee eeee eeeee eee eeeee (MeMM8). Meeeeee ee eee eeeeeeee eeee e eeeeeee, eeeee eee eeeeeeeee ee MeMM (8.8 eM) eee 88% ee MMe (8.8 eM) eee eeeee ee eee eeee. Mee eeeeeeeee eeeeeee eee eeeeeee ee ee eee 8.8 eee eee eee eeeeeeee eee eeeeeeee ee eeeeeeee ee eee. ee MeMMM8 ee 8 °M. Mee eeeeeeeee eeeeeee eee eeeeeee ee eeee ee ee eee eeeeeeeee eeee MM8Me8. Mee eeeeeee eeeee eee eeeeee eeee eeeee eee eeeee (MeMM8). Meeeeee ee eee eeeeeeee eeee e eeeee eeeeeee, eeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee) ee eeee eee eeeeeee.

(M)-M-(8-Mee-8,8-eeeeeeeeeeeeee)eeeeeeeee (‌88‌, M8 = Me); Meeeeee Meeeeeeee:[‌888‌]

M eeeee eeee eeee eee eeeeeee eeee M-eeeeeeeeeeee ‌88‌ (M8 = Me; 88.8 ee, 8.88 eeee) eee eee eeeeeeeeee eee eeeeeeee eeee M8. Mee eeeee eee eeeeeeeee ee eeeeeee (8.8 eM) eee e 8.888 M eeee ee eee eeeeee eeeeeeeeee eeee (M)-‌88‌ ee eeeeeee (8.8 eM, 8.8888 eeee) eeeeeeee ee eeeeee (8-eeeeeeeeeee)eeeeeeeee (88.8 ee, 8.88 eeee) eeee eeeee ee ee. Mee eeeeeee eee eeeeeee eee eeee 8 e ee eeeeeee eeeeeeeeeee, eee eeee eee eeeeeeee eee eeeeeeee ee eeeeeeee ee eee. ee MeMMM8. Mee eeeeeeeee eeee eee eeeeeeeee eeee MM8Me8 eee eeeee (Me8MM8). Mee eeeeeee eee eeeeeee, eee eeeeeee eee eeeeeeeee ee MeMM (8.8 eM), eee 88% ee MMe (8.8 eM) eee eeeee. Mee eeeeeeeee eeeeeee eee eeeeeee ee ee eee 8 eee, eee eeee eee eeeeeeee eee eeeeeeee ee eeeeeeee ee eee. ee MeMMM8 ee 8 °M. Mee eeeeeeeee eeeeeee eee eeeeeee ee eeee ee ee eee eee eeee eeeeeeeee eeee MM8Me8. Mee eeeeeeee eeeeeee eeeeee eeee eeeee (Me8MM8), eee eeeeeee eee eeeeeee, eee eee eeeee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee/MeMMe 8:8 ee 8:8) ee eeee eee eeeeeee ee e eeeee eeeee; eeeee: 88%; 88% ee.

References