Intermolecular [4 + 2] process of N-acyliminium ions with simple olefins for construction of functional substituted-1,3-oxazinan-2-ones

• Published in: Chinese chemical letters Vol. 32; no. 11; pp. 3526 - 3530
• Main Authors: Han, Xiaoli, Nie, Xiaodi, Feng, Yiman, Wei, Bangguo, Si, Changmei, Lin, Guoqiang
• Format: Journal Article
• Language: English
• Published: NEW YORK Elsevier B.V 01.11.2021; Elsevier; Institutes of Biomedical Sciences and School of Pharmacy,Fudan University,Shanghai 200433,China%Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032,China
• Subjects: Chemistry; Chemistry, Multidisciplinary; Intermolecular [4 + 2] process; N-acyliminium ions; Physical Sciences; Science & Technology; Simple olefins; Spiro; Substituted-1,3-oxazinan-2-ones; N-acyliminium ions; Intermolecular [4 + 2] process; Simple olefins; Substituted-1,3-oxazinan-2-ones; Spiro; ASYMMETRIC-SYNTHESIS; CARBON; Intermolecular [4+2] process; ALCOHOLS; HETEROCYCLES; ADDITION-REACTIONS; STEREOSELECTIVE-SYNTHESIS; ALKOXYCARBONYLIMINIUM IONS; CONCISE SYNTHESIS; STEREOCONTROLLED SYNTHESIS; ALKALOIDS; Intermolecular [4 + 2] process
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2021.05.003

An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones skeleton has been developed through the reaction of semicyclic N,O-acetals 4a and 4b with 1,1-disubstituted ethylenes 5 or 8. As a result of such a [4 + 2] cycloaddition process, 4,6,6-trisubstituted-1,3-oxazinan-2-ones 6aa, 6af-6au, 7ba, 7bf-7bw and 6,6-spiro containing 1,3-oxazinan-2-ones 9ad, 9ae, 10ba-10bg were obtained in 36%-96% yields and with moderate to excellent diastereoselectivities. In addition, the synthesis of (±)-norallosedamine 12 could be conveniently achieved from the cycloadduct 7bf. An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones skeletons has been developed through the reaction of semicyclic N,O-acetals with 1,1-disubstituted ethylenes. [Display omitted]