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. Issue 44 (7th September 2016)

• Record Type: Journal Article
• Authors: Hayashi, Yujiro; Bondzic, Bojan P.; Yamazaki, Tatsuya; Gupta, Yogesh; Ogasawara, Shin; Taniguchi, Tohru; Monde, Kenji
• Is Part Of: Chemistry. Volume 22:Issue 44(2016)
• Page Start: 15874
• Page End: 15880
• Publication Date: 2016-09-07
• Subjects: all-carbon quaternary stereocenter -- asymmetric reaction -- chirality -- Diels–Alder reaction -- organocatalysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201602345
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The asymmetric Diels–Alder reaction of α‐substituted acrolein proceeds in the presence of the trifluoroacetic acid salt of trifluoromethyl‐substituted diarylprolinol silyl ether 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 perchloric acid salt of the bulky triisopropyl silyl ether of trifluoromethyl substituted diarylprolinol was employed as an organocatalyst in the presence of water. In both cases, all‐carbon quaternary stereocenters are constructed enantioselectively. Abstract : All‐carbon quaternary stereocenters were constructed by asymmetric Diels–Alder reaction of α‐substituted and β, β‐disubstituted α, β‐enals in a highly enantioselective manner. Diarylprolinol silyl ether acts as an effective organocatalyst with a combination of an acid, and the reaction proceeds at 0 °C or room temperature in CH3 CN, or by using water as a green solvent. This is a practical enantioselective method for the synthesis of all‐carbon quaternary stereocenters.