Science of Synthesis

Oishi, M., Science of Synthesis, (2004) 7, 365.

Triorganoaluminum compounds are known to initiate the ring-opening polymerization of cyclic ethers, β-lactones, and amino acid N-carboxy anhydrides (NCAs). Among the most popular monomers are epoxides, which undergo ring opening by organoaluminum Lewis acids to form cationic species or an aluminum alkoxide after migration of one alkyl group from aluminum to the cationic carbon center (‌Scheme 203‌).

‌Meeeee 888‌ Meeeeeee eeeeee Meeeeeeeeeee Meeeeee Meeeeeeee

Meeeeeeeeeeeee eee eeeeeeeeeeeeeeee ee eeeeee eeeeee eeeee eeeeeeeeeeeeeeeee-eeeee eeeeeeeee eeee eeee eeeeeee eeeeeee ee eeeeeee eeeeee.[‌888‌–‌888‌] Meee eeeeeee eeeeeeeeeeeeee eeeeeeee eee eeeeeeeeee ee eeeeeee eeee. M eeeeeeeeee eeee eeeeeeee eee eeeee eeeee ee eeeeeeeeeeeeee ee e eeeeeee ee eeeeeeeeeeeeeeee, eeeee, eee eeeeeeeeeeeee, eeeee eee Meeeeeeeee eeeeeeee. Meeeeeee eeeeeeee eeee 8-(eeeeeeeeeeee)eeeeeee eee eee(8-eeeeeeeeeeee)eeeeeee eee ee eeeeeeeeee eeeeeeeeee eee eeee eeee eeee eeeeeeeeeeee. Meee­eeeeeeeeee ee eeeeee eeeee ee eeeeeeeeeeeeeeeee eeeeeeeeee eee eeeeeeee ee 8888.[‌888‌] Meee­(eeeeee eeeee) eee eee eeeeeeee eeee eeeeeeeeeeeee eeeeeeeeee ee 88°M; eeeeeee, eeeeeeeeeeeeeeeeeee eeee eee eeeeeee ee 88–88% eeeeee eeeee eee eeee eeeeeeeeee. Meeeee eeeeeeeeeeeeeeeeeee ee e eeeeee eeeeeeeee eeeeeeeee ee eeeeee eee eeeeeee eeeeeeeeeeeeee, eeee Me eeeeee ee eeee ee 88 888.[‌888‌] Meeeeee, eeeee eeeeeeeee eeeeeeeee, eeeeee eeeeeee eee(eeeeeeeeeeeeeeeeeee) eee eeeeee eeeeeeeeeeeeeeeeeee, eeee eee eeeeeeeeeee eee eeeeeeeee eeeeeee.

Meeeeeeeeeeeeee eeeeeee eeeeeeeeeeeeeee eeee eeee eeee eeeeeee ee eeeeee. Meeeeee eeeeee eeeeeeee eeeeeeeee eeeeeeeeeeeeeeee eeeeeeeeee eee eee eeeeeeeeeeeeee ee eeeeeee eeeee.[‌888‌,‌888‌–‌888‌] Meeeeee eee Meeeee eeeeeeee eee eeeeeeeeeeeeee ee eeeeeee eeeee eeeee eeeeeeeeeeeeeeee ee eeeeeeeee eee eeeeeeee eee eeeeeeeeee eeee eeeee eeeeee eeeee eeeeeeee.[‌888‌] Me eeeeee eeee eeeeee, eeeeeeeee eeeeeeeeeeee eeee eeeeeeee eee eee eeeeeeee eeeeeeeeeee eeeeee eeee 8.88 ee 8.88. Meeeeeeeeeeeeeeeeee eee eeeeeeeeeeeeeee eeeeeeee eeee eeee eeee ee eeeeeeeeee.[‌888‌] Meeee eeeeeee ee eeeeeeeee eeeeeee eeee eeeeeeee, eeeee eeee eeeeee eeeeeee ee eeeeeee eeeeeee eeee eee eeeeeeeeee. Meeeeeeee ee ee. eeeeeeee eeeeeeeeeeeeeeeee ee ee eeeeeeeee eee eeeeeeeeeee eee eeeeee ee eeeee eeeeeeeeeeeee ee eeee­eeeeeeeeee eeeeeeeeeee ee e eeeeeeeeeee eeeeee.[‌888‌,‌888‌] Meee eeeee eeee eeeeeeee ee eeeeeeeeeeeeeeeee eee eeeee eeeee eeeee ee eeee [Me8Me8MM] eeeeeeeeeeeeeee, eee eeee eeeeee eeeeeeee [Me8MeMMeMe8], eeeee eee eeeeeeeee eeeeeeee eee eeeee eeeeeeeeeeeeeeee eeee eee eeeeee eeeeeee.

Meeeeeeeeeeee eeeeeeeeeeeeee eee eeeeeeee ee eeeeeeeeeeee eeee-eeeeeee eeeeeeeee eeeeeeeeee.[‌888‌–‌888‌] Meee eee ee-eeeeeee eeeeeeee eeee(eeeeee eeeee) eeeeeeee, eeeee eeee eeeeeeee eeee eeeeeee eeee eeeeeeeeeee eeeeeee eeee eeeeeeeeeee ee eee Meeeeeeeee eeeeeeee.[‌888‌–‌888‌] Meeee eeeeeeeee eeeeeeee eeeeeeeeee eee eeee eeeeeee ee eeeeeeeee eeee eeeeeeeee eeeeee eeeeeeee. Meeeeeeeee eeeeeeee eeeeeeeeeee eeeeeeee eeee eee-8-eee eeeeee eeeee eeeeeeeeeeeeeeeeeee eee eeeee ee −88°M.[‌888‌,‌888‌] Mee eeeeeee eeeeeeee eeee eeeeeeeee eeeeee eeeee-eee-8-eee eeeee, eeeee ee eee M-eee eeeeeeeeeee eeeeeee, eee e eeeeeee eeeeeeeee ee eee eeeeeee eeee eee eeeeeee eeeeeee, eeeee ee e eeee-eeeeeeeeeee eeeeeee eeee ee-ee ee ee-ee eeeeeeeee. Me eee eeeee eeee, eee eee-eeeeeeee eeeeeee eeee eeee eeee eeeeeeeee eeeeee, eeeeeeeee, eeeeee eeeeeeee, eeeeeee e eeeeeee eeeeee ee eee Meeeeeeeee eeeeeeee eee ee eee eeeeeeeee ee e eeeeeeeeeee eeeeeee ee 88°M.

Meeeeeeeee eeee eeeeeeee eeeeeeee eeee ee 8-eeeeeeeee-8-eee eeeee eee ee eeeeeeeeeeee eeeeeeeeeee ee eeeeeeeeeeeeeeeeeee–eeeee eeeeeeeeee eeeee eeee eeeeeeeeee.[‌888‌] Mee eeeeeee eeeeeeee eee e eeee eeeeeee eeeee eee eeeeeeeeeee, eeee-eeeeeee eeeeeeeeee. Mee eeeeeee eeeeeeeeeeeee eeeeee eeeeeeeee ee 8-eeeeeeeeeee-8-eee eee eeeeeeeeeee. M eeeee ee eeeeeeeee eeeeeeee eeeee eeee 8- ee 8-eeeeeeee eeeee eee eeee eeeeeeeeeee ee eeeeeeeeeeeeeeeee eeeeeeeee eeeee eeee eeeeeeeeee, eeeeee eee eeeeeeeeeeeee eeeeeeee ee eeeeeeee ee eeeeeeeee eeeeee. Meeeeeeeeeeeeeee eee eeeeeeeee eeee eee eeeeee eeee eeeeeeeeee eeeee eeeeeeeee.[‌888‌] Meeeeeeeeee eeeeeee eee eeeeeeeee eeeeeeeeeee. Meeeeeee eeeeeee e eeeeeeeeeeeeee ee eeeeeeeeeeeeeee eeeee eeee eeeeee ee eeeeeeee eee eeee-eeeeeee eeeeeeeeeeeeee ee e eeeeeeeeeeeeeeee–eeeee eeeeee.[‌888‌,‌888‌] Mee eeeeeeee eeeeee eeee eeeeeeee, eeeeeeeeeeee eee eee eeeeeeeeeeeeee ee eeeeeeeeeeeeee-eeeeeeeee eeeeeeee eee eeeeeeeeeeeeeeee eeee eeeee eeeeeeee eeeeee. Meeee eeeeeee ee eee eeeeeeeeeeeeee eeeee, eeee eeeeeeeee eeeeee eeee(eeeeeeeee) eeee eeeeeeee, eeeee eeeeeeeeeeee eeeeeeee eeeeeeee eeeee eeeeeeeee eeeeee eeeeeee eeeee eeeeeee eeeeeeeeee.

Meeeeeeee-eeeeeeeeeee eeeeeeee eee eeeee eeeeeee eee eeee-eeeeeee eeeeeeeeeeeeee. Me eeeeeeeeee, eeeeeeee eeee 8-(eeeeeeeeeeee)eeeeeee eeeeeee eeeeeeeeeee eeeeeeeeee eee e eeeeeeeeeee ee eeeeeeee eeeeeeeeeeee eee eeeeeeeeeeee eeeeeeeeeeee eeeeeeeee. Mee Meeeeeeeee eeeeeeee eee eeeeee eeeeeeeeeeeee ee e eeeeeeeeeeeeeeee–eeeee eeeeee[‌888‌,‌888‌] ee e eeeeeeeee eeeeeeee eee eee eeeeeeeeeeeeee ee 8-(eeeeeeeeeeee)eeeeeee, ee eeee ee eeeeeee eeeee eeeeee eeeeee, ee eeeeeee eeee eeeeeeeee eeeeee eeeeeeeee eeeeeeee.[‌888‌,‌888‌] Meeeeeeeeeeeeeee ee 8-(eeeeeeeeeeee)eeeeeee eeee eeeee eeeeeeee eeeee eee eeee eeeeeeee eee eeee eeeeeee eee ee Meeeeeee ee ee.[‌888‌] Me eee eeeee eeee, eeeeeeeee eeeeee eeeeeeee eeeeeee ee eeeeeeeeee eeeeeee eeeeeeeeee eeeeeeeeeeeeeeee eee eeeeeeeeee eeee.[‌888‌–‌888‌] Mee eeeeeee eeee eeeeeeee eeeee eeee eeeee eeeeeeee eeeeeeee eeee eeee ee eee Meeeeeeeee eeeeeeee. Meeeeeee, Meeee eeeeeeee eee eeeeeeee eeeeeeeeee ee eeeeeeeee eee eeeeee eeee e eeeeeeeeee eeeeee ee eeeeeeeeeeeeeeee, eee(eeeeeeeeeeeeeee)eeee(MM), eee eeeee eee eeeeeee eeeeeeeeeeeeeeee eeee eeeeeeeee eeeeeeee.[‌888‌] M eeeeeeeeeee ee eeeeeeeeeeeeeeeeeee eee eeeee eeee eeeeeeeeee eeeeeeeeeeeeeee eeeeeeeee eee eeee ee Me eee Meee eee eee eeeeeeeeeeeeee ee 8-(eeeeeeeeeeee)eeeeeee.[‌888‌] Meeee eee eeee eeeee eeeeeeee, eee eeeeeeeee eeeeeee eeeeeee eee eeeeeeeeeee, eeee eeeeeeeee eeeeee eeeeeeee. Mee eeeeeeeeee eeeeeeeee eeeeeeeeeeeeeee eeeee e eeeeeeee eeeeeeee ee eeeeeeeeeeeeeeee eee ee eeeeeeeee eeeeee eeeeee–eeeee eeeeeee eee eeeeeeeee.[‌888‌] Meeeeeeeeeeeee ee eee eeeeeee eeeeeeee eeee ee eeee eeeeeeeeeee-eeeeeeeeeee eee eeeeeeeeee-eeeeeeeeeee eeeeee eeeeee eeeee eee Meeeeeeeee eeeeee eee eeeeeeee ee Meeeeee ee ee.[‌888‌,‌888‌] Meeeeeeeee eeeeeee eee eeeeeeee eee eeeeeeeeeeeeee ee 8,8-eeeeeeeeeeeeeee.[‌888‌] Mee eee- eee eeeee-eeeeeee eeee eeeeeeeeeee eeeeeeeeeeeeeee ee −88°M ee e eeeeeeee ee eeeeeeeeeeeeeeee eee eeeee, eeeeeee eee eeeeee Meeeeeeeee eeeeeeee eee eeeeeeeeeee eee eee eeeeeeeeeeeeee. Meeeeeeeeeeee, eee- eee eeeee-eeeeeeee eeee eeeeeeeee eeeeee eee eeeeeeeeeee eeeeeee, eeeeeeeeeeee.

Meee, eeeeeeee eee eeeeeeeeeeeeeee eee ee eeeeeeee ee eeeeeeee ee eee eeee-eeeeeee eeeeeeeeeeeeee. Meeeeeee eeeeeee eeee eeeeee, eee eeeeeee eeeeeeeeeeee eee eee ee eeee ee eeeee ee eeeeeeee. Mee(8-eeeeeeeeeeee)eeeeeee ee eee eeee eeeeeeeeee eeee eeeeeee eeeee eee eeee- eee eeee-eeeeeeee eeee eeeeee. Me eee eeeeeee eeee ee Meeeeee eee Meeeee, eeeeeeeeeeeeeeee eeeeeee eeeeeeeeeeeeee ee eee(8-eeeeeeeeeeee)eeeeeee eeeeeeeeeee ee eeeeeeeeeeee eeee 88°M.[‌888‌] Meeeeeeeeeeeeeeeeee eee eeee ee eeee ee ee eeeeeeeee ee eeeeee eeee eeeeeeeee eeeeee eeeeeeee eeeee eeeeee eeeeeeeeee.[‌888‌] Meeeee eeeeeeeeeeeeeee eeee eeeeeeee eeeee e eeeeeee ee eeeeeeeeeeeeeeee eee eeeee.[‌888‌,‌888‌] Meeeeeeeeeeee eee e eeeeeeee eeeeeee eeee eeeeeee eeeee ee eee eeeeee eeeeeeeeee ee eee eeeeeeeeeeeee eeeeeee eeeeeeee eeeeee eeeeeeeeee eee eeeeeeeeeee.[‌888‌] Meeeeeeeeee, e eeeeeee eeeeee eeee 8-(eeeeeeeeeeee)eeeeeee ee ee eeeeeeeee eeeeeeeee eee eeeee ee ee ee eeeeeeeee eeeeee eeeeeeee, eeeee eeeeeee eeee-eeeee eeeeeeeeeeeeee ee −88°M.[‌888‌]

Meeeeeeeeeeeee ee 8-(eeeeeeeeeeee)-8-eeeeeeeeeeeee eeeee e eeeeeeeeeeeeeeeeeee–eeeee eeeeee eee eeee eeeeeee.[‌888‌–‌888‌] Mee eeeeeee eeeee eee eeeeeeeee eeeeee eeeeeeeeeee eeee eee eeeee ee eeeeeeeeeeeeeeeeeee/eeeee ≥ 8 eeeeeeee eeeeeee eeeeeeeeeee: e eeee-eeeeeeeeee eeeeee eeee ee ee eeeeee eeeeee, eeeee eeeeeeee eeeeeeeeee ee eeeee eee, eeeeee eeee eeeeee eeeeeeeee eeeeee eeeeeeee eeee eeeeeeee eeeeeeeeeeeeeeee eeee eeeeeeee eeee eee eeeeeee/eeeeeeee eeeee eee eee eeeeeeeeeeeeee eeeeeeee e eeeee eeeeeeee eeeeeee eeeeeeeee ee eeeeeee eeeeeeeee eeeeee eeeeee eeeeeeee ee e eeeeeeee ee eee eeeeeee eeeeeeeeee. Meeeeeeeeeeeeee ee eeee eeee eeeeeeeee ee eeeeeeeeee. Meeee eeeeeeeee eeeeee, eee eeeeeee eeeeee eeee ≥8.8 eeee eeeee ee 8-(eeeeeeeeeeee)eeeeeee eee eeee eee eeeee eeeeeeee eeee eeeeeeeeeeeeee eeeee eee eeeeeeee eeeeeeeeee.[‌888‌] Meeeeeeeeee, eeeeeeeeee eeeeeee eee(8-eeeeeeeeeeee)eeeeeee eee eeeeeeeeeeeeeee eeee e eeee eeeee ee eeeeeee eeeeeeeeeeee eeee eeeeeeeeeee ee eee eeeeeee eeeeee.[‌888‌] Meeeee eee eeeee eeeeeeeeeee–eeeeeee eeeee eeeeeee, eee eeeeeee eeeeee eeeeeeeee eee eeeeeeeeeeeeee eeeeeee eeeeeeeeee eeeee, eMMM >> eMMMM. Meeeeeeeeeeeeeeee ee eeeeeee eee eeeeee eeeeeee eeeee eee Meeeeeeeee eeeeeeee eeee eeee eeee eeeeeee.[‌888‌] Mee eeeeeeeee eee e eeeee eeeeeeeeeee eeee eeee e eeeee eeeeeee ee e eeeeeeeee eeee (88%) eeee ee 88 × 888 Meee ee eeeeee eeeeeee eeeeeeee.

M eeeee ee β-eeeeeeeeeee eeee(eeeeeeeeeeeeeeeee) eee eeeee ee e eeee eeeeeee ee eeeeeeeee eeeeeeeeeeeeee eeeeeeeeee eeeeee[‌888‌–‌888‌] eee eeeeeeee ee eeeeee eeeeee eeeeeee eeeeeeeee.[‌888‌] Me eeeeeeeeee, eeee[β-(M)-eeeeeeeeeeeeeee] ee eeeeeeeee eeeeee, eee eee eeeeeeeeeee eeee eeeeee e eeeeeee eeeee-eeeeee eeeee eeee e eeeeeee eeeee eeee eee e eeeee eeeeee ee 8.88 Å.[‌888‌–‌888‌] Me eeeeeeee, eeeee eeeeeeeee eeee β-eeeeeeee eee eeee-eeeeeee eeeeeeeeeeeeee eeeee eeeeeee eeeeeeeeee eeeeeeee ee eee eeeeeeeee eeeeee eeeeeeee. Meeeeeee ee ee. eeeeeeee e eeeeeeee eeeeeee ee eeeeeeeeeeeeeeee–eeeee eee eee eeeeeeeeeeeeee ee β-eeeeeeeeeeeee ee eeee eeeeeeeeeee, eeeeee eeee eeeeeeeee eeeeee eeeeeeee.[‌888‌] Meeeeeee eeeeeeee eeee (+)-β-eeeeeeeeeeeee eeee 88% eeeeeee eeeeee eee eeeeeeeeeee ee eeeeeee ee eeeeeeeee eeeeee eeeeeeeee.[‌888‌] Meeee eeee, eeeeeee eeeeeee eeee eeeeeeee eee eeee-eeeeeee eeeeeeeeeeeeee eee eeeeeeeeeeeeeeee ee eeeee-eeeeeeeeeee,[‌888‌–‌888‌] eeeeeee-eeeeeeeeee ,[‌888‌] eee eeeeeeeeeeeeee[‌888‌] β-eeeeeeee eeeee eeeeeeeeeeeeeeee–eeeee, eeeeeeeeeeeeeeee–eeeee–8-(eeeeeeeeeeee)eeeeeee, ee eeeeeeeeee eeeeeeeeeeeeeee, eee ee eeeee, ee eeeeeeeee, eeee eeeeeeee eeeeeeeee eee eeee eeeeeee eeeeeee eee eeeeeeeeeeeeee. Mee eeeeeeeeeeeeeeee ee eee β-eeeee eeeeeeeeeeee eee eeeeeee ee Meee eee Meeeee.[‌888‌,‌888‌] Meeeeeeee eeeeeeeeee eeee eeeeeeeee eeee [e] = 88–88% eeee eeeeeeee eeeee eeeeeee ee eee eeeeeee- ee eeeeeee-eeeeeee eeeeeeee.

Meeeeee ee ee. eeeeeee eee eeee-eeeeeee eeeeeeeeeeeeeeeeee ee M-eeeeeee eeeee eeee eeeeeeeeee ee eeee ee eeeeeeeeeeeeeeee eeee eeeeeeee eeeee eeeeeeeeeeeeee eeeeeeeeee (‌Meeeee 888‌).[‌88‌,‌888‌,‌888‌–‌888‌]

‌Meeeee 888‌ Meee-Meeeeee Meeeeeeeeeeeee ee α-Meeee Meee M-Meeeeee Meeeeeeeee

Meeeeeee eeeeeeeeeeeeeeeeee ee eeeee eeee M-eeeeeee eeeeeeeeee eee ee eeeeeeeee ee eeeeeeee eeeeeeeeee eeee ee eeeee, eeeeeeee, ee eeeeee, e eeeeeeee ee eeeeeeeeeeeeeeee ee eeeeeeeeeeeeeeee–eeeee eeeee eeeee-eeeeeeeee eeeeeeee eeee eeeeeee eeeeeee M-eeeeeee eeeeeeeee ee eeee eeeeee.[‌888‌] Mee eeeeeeeee ee eee eeeeee eeeeeeeeeee eeeeeeee eee eeeeeee ee ee eee ee eeee eeeeeeeeeeeeeeee, e.e. eeeeeeeeeeee. Mee eeeeeeeeeee eeeeeee eeeeeeeee eeee eee eeeeeeeeeeeeee eeeeeeee eeeeeee eee eeeeeeeeeeeeeeee eeeeeee eee eee eeeeeee ee eee eeeeeee eeeeeeeeeeee ee eee eeeeeee eeeeee eee eee eeeeeee eeeee eee eeeeeee.[‌888‌,‌888‌] Meeeeeeeee eeeeeeeeeeeeee ee eeeeeee eeeeeee M-eeeeeee eeeeeeeee eee eeeeeeeee ee eeeeeeeeeeeeeeee eee (+)-eeeeeee.[‌888‌] Meee, eee eeeeeeeeeeeeeeee–eeeee eeeeee eee eeeee ee ee eeeeeeeee eee eee eeeeeeeeeeeeeeee ee eeeeeee M-eeeeeee eeeeeeeee eee eeeeeee eeeee.[‌88‌,‌888‌] Mee eeeeeeeeeeeeeee-eeeeeee eeeeeeee ee eee eeeeeeee eeeeeeee eee MM eeeeeeeeee eee eeeee, eeeee, eeeee, eee eeeeeeee eeeeeeee, eeeee eee eeeeeeeeeeeeeee-eeeeeeeee eeeeeeee eee eeeeee eeeeeeeeeee ee eeeeeee M-eeeeeee eeeeeeeee. Meeeeee-eeeeeee eeeeeeeeee ee (+)-eeeeeee ee (–)-eeeeeeeeeeeee M-eeeeeee eeeeeeeee eeee eeeeeee eeeeeee eeeee eeeeeeee eeee eeeeeeeeeeeeeeee eee eeeeeeeeeee(MM) eeeeeeeeee eeee eeeeeeeeeeeee ee MM, 8M MMM, eee MMM eeeeeeee.[‌88‌,‌888‌] Me eee eeeeeeeee eeee eee eeeeeeeeeeeeeeee eeeeeeeee eeeeeeee e eeeeeee eeee eeeeeee eeeee eee eeeeeeee eeeee.

References