Asymmetric, Organocatalytic Bromolactonization of Allenoic Acids
摘要:
Asymmetric, reagent-controlled bromolactonizations of allenoic acids have been achieved by using (DHQD)(2)PHAL as catalyst. A range of substrates can be cyclized in good yields and moderate to good enantioselectivities under operationally simple conditions.
The cascadecyclization reactions of 1,5-bisallenes grant access to a great variety of products by precisely tuning the catalyst system and/or the reagents involved. Herein, we present our findings that 1,5-bisallenes react with two molecules of dimethyl acetylenedicarboxylate to afford, in a completely diastereoselective manner, cis-3,4-arylvinyl pyrrolidines and cyclopentanes. DFT calculations have