Science of Synthesis

Liu, L.; Wang, D.; Li, C. -J., Science of Synthesis: Stereoselective Synthesis, (2011) 2, 601.

An efficient synthetic route has been developed for the synthesis of enantioenriched 3-hydroxy-2-methylpropanoates (e.g., ‌63‌) using N-methylephedrine ester as a chiral auxiliary group to form chiral silyl ketene acetals (e.g., ‌19‌) via the condensation product ‌62‌ (‌Scheme 27‌).[‌13‌] By this route α-amino and α-hydrazino acids,[‌56‌] as well as trans-β-lactams[‌57‌] have been synthesized in high enantiomeric excess and good chemical yields.

‌Meeeee 88‌ Meeeeeeeeeeeeeeeee Meeeeeeee Meeee Meeeeeee Meeee e Meeeee Meeee Meeeee Meeeee Meeeeee eeee M-Meeeeeeeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee

Meeeee (8M,8M)-8-Meeeee-8-eeeeeee-8-eeeeeeeeeeeeeeee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeeeeeeeeee ee eeeeeeeee ee eeeee, eeeeeeee, ee eeee, eee ee eeeeee eeeee ee eeeeeeeeee.

M eeee ee MeMMM (8 eeee) ee MM8Me8 (8 eM) eee eeeeeee eeee 8.8 M MeMe8 ee MM8Me8 ee −88 °M, eeeee M8, eeee eeeeeeee. Meeeeeeeeee eeeee eeee, e 8.8 M eeee ee eee eeeee eeeeee eeeeee ‌88‌ ee MM8Me8 (8.88 eM) eee eeeeee eeeee ee −88 °M. Meeee 8 e ee −88 °M, eee eeeeeee eee eeeeeeee eeee 8% MeMMM8 eee 8.8 M ee MeMM eee eeeeeeee eeeeeee Meeeee. Mee eeeeeee eeeee eee eeeeeeeee eeee MM8Me8, eee eee eeeeeeee eeeeeee eeeeeeee eeee eeeee eee eeeeeeeeeeee ee eeee eee eeeee eeeeeeeeeeee eeeeeee ‌88‌; eeeee: 88%; eeeee (eeee/eee) >88:8; ee (eeee-eeeeee) >88:8.

M eeee ee eee eeeee eeeeeeeeeeee eeeeeee ‌88‌ (8.8 eeee) ee MeMM/M8M (8:8; 88 eM) eee eeeeeee eeee MeMM (888 ee, 88.8 eeee) ee ee, eeee eeeeeeee. Meeee 88 e ee ee, eee eeeeeee eee eeeeeee eeee M8M (8 eM), eee MeMM eee eeeeeee eeeee eeeeeee eeeeeeee. Mee eeeeeeeee eeeeeee eeeeeee eee eeeeeee eeee 8 M MMe (88 eM) eee eeeeeeeee eeee MM8Me8. Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee eee eeeeeeeeeeee ee eeee eee eeeee eeee. M eeee ee eee eeeee eeee ee Me8M/MeMM (8:8) eee eeeeeee eeee MM8M8 ee eeee eee eeeee eeeeeee, eeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee/MeMMe 8:8); eeeee: 88%; 88% ee. [α]M88 +88.8 (e 8.88, MMMe8). Meeeeeeeeee M-eeeeeeeeeeeeeee eee eeeeeeeee.

References