Science of Synthesis

Tang, X.; Shi, M., Science of Synthesis: Metal-Catalyzed Cyclization Reactions, (2016) 1, 250.

The total synthesis of (−)-α-kainic acid through ene–cycloisomerization of methylenecyclopropanes has been accomplished by the Evans group (‌Scheme 91‌).[‌76‌] A key and striking feature of this protocol is that the alkene geometry does not have an impact on the efficiency or the diastereocontrol: (E)- and (Z)-allylic substrates ‌373‌ furnish the corresponding aldehydes ‌374‌ with similar efficiencies and selectivities. In addition, similarly derived diene products ‌375‌ are also very versatile building blocks in organic synthesis.

‌Meeeee 88‌ Meeeeee-Meeeeeeee Mee–Meeeeeeeeeeeeeeeee ee Meeeeeeeeeeeeeeeeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

‌Meeeeeeeeee 88M‌

Meee eeeeeeeeeee eee eeee eeeeeee ee eee eeeee eeeeeeeee ee (−)-α-eeeeee eeee (‌Meeeee 88‌).[‌88‌] Meee eeeeeeeee ‌888‌, eee eee eeeeeee-eeeeeeeee eee–eeeeeeeeeeeeeeeeee eeeeeeee eeeeeeee eeeeeeee ee eeeeeee eeee,eee-8,8,8-eeeeeeeeeeeeee eeeeeeeeeee eeeeeeee ‌888‌ ee 88% eeeee eeee eeeeeeeee eeeeeeeeeeeeeeeeeeee (ee >88:8). Meeeeeeeee eeeeeeeee eeeee eeeeeeeeee eeeeeeeeee eeeee eeeeeeeeeeee ‌888‌, eeeee ee eeeeeeeee eeee eeeeeee ‌888‌ eeee eeeeeeeeee eeeee eeeee eeeeeeeeee. Meeee eeeeeee eeeee eeeeeeeeeeeeeee, (−)-α-eeeeee eeee ee eeeeeeee. Meeeeee, eeee eeeee eeeeeeeee eeeeeeeeee eee ee eee eeee eeeeeee eee eeeeeeeee eeeeeeeeeeee eeee eee ee eeeeeeee eee eeeeeeeeee eeeeeeeeeee.

‌Meeeee 88‌ Meeee Meeeeeeee ee (−)-α-Meeeee Meee[‌88‌]

Meee eee eeeeeeeeeeee eee eeeeeeeeeeeeeee eeeeee eeeee eeeeeeeee ee (+)-eeeeeeeeeeee eeeee e eeeeeeeeeeee eeee-eeeeeee ee e eeeee–eeeeeeee eeeeeeeeeeee (‌Meeeee 88‌).[‌88‌] Mee eeeeeeee ee eeeeeeeee eeee eeeeeeeeeeee ‌888‌ eee eeeeee ‌888‌ ee eee eeeeeeee ee eee(eeeeeeeeeeeeeeee)eeeeeeeeeee eeeee eee eeeeeeeeeeeee eeeeeeeeeee eeeeee ‌888‌, eee eeeeeeeeee Meeeee eeeeeeee eeeeeeeee eeeee eeeeeeeeeeee ‌888‌. Meee, eeeeeeeeeeee eeee eeeeeee eeeeeeeee ee e Meeee eeee eeeee ee eee eeeeeeeee ee eeeeeeeee eeeeeeee ‌888‌. Meeeeee ee eee ee eee eeeee eeeeee ee Meeeeee eeeeeeeeeeeeeee eeeee eeeeeeeee eeeeeeeeeee eeeee eeeeeeeee ‌888‌, eeeee eee eeeeeeeee ee eee eeeeeeee ee e eeeeeeeeee eeeeeeee eeeeeeeeeeee eeeeeeeeeeee.[‌88‌] Meeeeeee eeeee eee eeeee eeeee eeeee eeee eeeeee eee eeeeee eeeeeee eeeeeee, eeee eeeeee eeeeeeee eeeeee eeeeee ee eeeeeeeeeeeeee eeeeeeee eeeeeee.

‌Meeeee 88‌ Meeeee Meeee Meeeeeeee ee (+)-Meeeeeeeeeee[‌88‌]

Me eee eeeee eeeeeeeee ee (±)-eeeeeeeee,[‌88‌] Mee eee eeee e eeeeeeeeeeee eeee-eeeeeee eeeeeeeeee eeeeeeee ee eeeeeeeee eeee-eeeee eeeeeeee eeeeeeeeee. Meee eeeee eeeeeeee ‌888‌, eeeeeeeeeeeeeeee ee eee eeeeee eeeee eeeeeeeeeeee ‌888‌, eeeee eeeeeeee ‌888‌ eeee e eeee-eeeeeee eeeeeee. Meeeeee-eeee eeeeeeee ee ‌888‌ eeeeeee ee eee eeeeeeeeeeee ‌888‌, eeeee eeee eeeee ee eee eeeee eeeee eeeeeeeee ee eee eeeeeeeeeee eeeeeeee (±)-eeeeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeee Meeeeeeee ee (±)-Meeeeeeee[‌88‌]

Meeee ee eeeeeeeeeeeeee eeeee-eeeeeeeeeeeee eeeeeeee eeeeeeee, Meee eeeeeeeeeeee eeeeeeeee e eeeeee eeeee eeeeeeeee ee eeeeeeeeeeeee.[‌88‌] Meeeeeee eeeeeeee ‌888‌ eee ee eeeeee eeeeeeeeeee ee eeee eeeee ee eeeeeeeee eeeeeeee ee eeeeee ‌888‌. Meee, ee eee eeeeeeee ee eeeeeeee(MMM) eeeeeeeeeeeeeeeeeeeeeeeee, eeeeeeeeeeeeee eeeee-eeeeeeeeeeeee eeeeeee eeeee eeeee ee eeeeeeeee eee eeeeeee eee-eeeeeee eeeeeeeeeee ‌888‌. Meeeeeeeeeeeeee eeeeeeee eeeeeeeee ‌888‌, eeeee ee eee eee eeeeeeeeeeee ee eee eeeeeeeee ee eeeeeeeeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meeeee Meeee Meeeeeeee ee Meeeeeeeeeeee[‌88‌]

Me e eeeee eeeeeeeee ee eeeeeeeeeeee, Meeee eee eeeeeeee eeee eeeeeeeeeeeee ‌888‌, eeee eeeeee eeeee eee eeeeeeeeeee eeeeeeeeeeee ee e eee eeeeeeeeeeee, eee ee eeeeeeeee eeee eeee-eeeeeeee eeeeeeeeeeeee eeeeeeeeee ‌888‌.[‌88‌] M eeeeeee eeeee eeeeeeeeeee ee eeeeeee ee eeee eeeee, eeeeeeeeee eee eeeeeeeeeee eeeeeeee eeeeeeeeeeee ‌888‌, eeeee eeeeeee eeee eeeeeeeee ee eee eeeeeeeeeeeee. Mee eeeeeeeee eeeeeeeeeeeee ‌888‌ ee eeeeeee eeeeeeeee eeee eee eeeeeee eeeeeee eeeeeeeeeeee (‌Meeeee 88‌).

‌Meeeee 88‌ Meee-Meeeeeeee Meeeeeeeeeeeeeeeee: Meeee Meeeeeeee ee Meeeeeeeeeee[‌88‌]

Mee eeee-eeeeeee ee eeeeeeeeeee eeeee eeeeeeee ‌888‌ eee eeee eeeeeeeee eeeeeee ee Meee ee eee eeeee eeeeeeeee ee eeeeeee ee eee eeeeeeeeee eeeeee ee eeeeeee eeeeeeee eeee e eeeeeeeeeee eeee, eeee ee eeeeeeeeeeeeee M, eee eeeeeeee eeeeeeeee ee eeeee ee eeeee ee ‌Meeeee 88‌.[‌88‌] Mee eeeeeeeeeeee ‌888‌ ee eeeeee eeeeeeeeeee ee eeeeeee-eeeeeee eeee eeeeeeeee ee eee eeeeeeee eeeeeeeeeeee.

‌Meeeee 88‌ Meeee Meeeeeeee ee Meeeeeeeeeeeee M[‌88‌]

References