Asymmetric Carbamoyl Anion Additions to Chiral N-Phosphonyl Imines via the GAP Chemistry Process and Stereoselectivity Enrichments

作者：Seifert, Cole W.; Pindi, Suresh; Li, Guigen^*

来源：Journal of Organic Chemistry, 2015, 80(1): 447-452.

DOI：10.1021/jo5024443

• SULFINYL IMINES
• REDUCTIVE AMINATION
• AMINE SYNTHESIS
• REAGENTS
• KETONES
• DESIGN
• ACIDS

Carbamoyl anions were found to smoothly react with chiral N-phosphonyl imines in toluene at -78 degrees C to r.t. using LiHMDS as the base. Group-assisted purification (GAP) has been utilized to give the pure amides without using column chromatography or recrystallization. The asymmetric reaction resulted in chiral N-phosphonyl amino amides with good to excellent yields (71-99%) and good crude diastereoselectivities (dr 84:16-95:5). In this GAP procedure, the crude solids are washed with diethyl ether to afford the pure products, as revealed by H-1 NMR analysis; GAP washing consistently increases the diastereopurity of the products, resulting in excellent diastereoselectivities, often with final dr > 99:1. Interestingly, the diastereoenriched products can be obtained either in the ether solution or as the suspended solid, depending on the substrate.

• 单位
  南京大学