Exploring the Steric and Electronic Factors Governing the Regio- and Enantioselectivity of the Pd-Catalyzed Decarboxylative Generation and Allylation of 2‑Azaallyl Anions

• Published in: Journal of organic chemistry Vol. 83; no. 7; pp. 4054 - 4069
• Main Authors: Wang, Shuaifei, Qian, Xiaoyan, Chang, Yuanyu, Sun, Jiayue, Xing, Xiujing, Ballard, Wendy F, Chruma, Jason J
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 06.04.2018; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; ASYMMETRIC UMPOLUNG ALLYLATION; HOMOALLYLIC AMINES; IMINES; AMINO-ACID DERIVATIVES; BOND-FORMING REACTIONS; ARYLATION; ESTERS; EQUIVALENTS; PARAMETERS
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/acs.joc.8b00491

The impact of the steric and electronic factors in both the para-substituted benzaldimine and 2,2-diarylglycine components on the regioselectivity and enantioselectivity of the palladium-catalyzed decarboxylative allylation of allyl 2,2-diarylglycinate aryl imines was explored. These studies revealed that using 2,2-di­(2-methoxyphenyl)­glycine as the amino acid linchpin allowed for the exclusive synthesis of the desired homoallylic benzophenone imine regioisomers, independent of the nature of the imine moiety, in typically high yields. The resulting enantiomeric ratios, however, are slightly decreased in comparison to the transformations involving the corresponding allyl 2,2-diphenylglycinate imines, but this is more than balanced out by the increases in yield and regioselectivity. Overall, these studies suggest a general strategy for the highly regioselective functionalization of 2-azaallyl anions.