Alkyne-Enol Ether Cross-Metathesis in the Presence of CuSO4: Direct Formation of 3-Substituted Crotonaldehydes in Aqueous Medium
摘要:
An efficient synthesis of 3-substituted crotonaldehydes via alkyne-enol ether cross-metathesis in the presence of CuSO4 and in aqueous medium was developed. Crotonaldehydes were obtained in good yields from terminal aryl-alkynes as well as from terminal alkyl-alkynes. All of the reactions were carried out under microwave irradiation and were completed in a few minutes. Water was used as the cosolvent, making c, this approach safer, economic, and desiderable from an enviromental point of view.
Asymmetric Diels-Alder Reaction of α-Substituted and β,β-Disubstituted α,β-Enals via Diarylprolinol Silyl Ether for the Construction of All-Carbon Quaternary Stereocenters
作者:Yujiro Hayashi、Bojan P. Bondzic、Tatsuya Yamazaki、Yogesh Gupta、Shin Ogasawara、Tohru Taniguchi、Kenji Monde
DOI:10.1002/chem.201602345
日期:2016.10.24
Diels–Alder reaction of α‐substituted acrolein proceeds in the presence of the trifluoroacetic acid salt of trifluoromethyl‐substituted diarylprolinol silylether to afford the exo‐isomer with both excellent diastereoselectivity and high enantioselectivity. In the Diels–Alder reaction of a β,β‐disubstituted α,β‐unsaturated aldehyde, good exo‐selectivity and excellent enantioselectivity was obtained when the