Design, Synthesis, and Applications of Chiral <i>N</i>‑2-Phenyl-2-propyl Sulfinyl Imines for Group-Assisted Purification (GAP) Asymmetric Synthesis

A new chiral (<i>R_s</i>)-2-phenyl-2-propyl sulfinamide has been designed and synthesized; its derived aldimines and ketimines have been applied for asymmetric addition reaction with allylmagnesium bromide. The reaction was conveniently performed at room temperature to give a series of homoallylic amines in high yields (up to quant) and diastereoselectivity (up to >99% de). The pure products were obtained by relying on group-assisted purification (GAP) chemistry to avoid traditional purification methods of column chromatography or recrystallization. The conversion of disulfide to (<i>R</i>_<i>s</i>)-thiosulfinate which contains a newly generated polar group was also confirmed to be of the GAP chemistry in which washing crude product can generate pure enantiomer. The absolute stereochemistry has been determined by X-ray analysis

Design, Synthesis, and Applications of Chiral <i>N</i>‑2-Phenyl-2-propyl Sulfinyl Imines for Group-Assisted Purification (GAP) Asymmetric Synthesis

A new chiral (<i>R_s</i>)-2-phenyl-2-propyl sulfinamide has been designed and synthesized; its derived aldimines and ketimines have been applied for asymmetric addition reaction with allylmagnesium bromide. The reaction was conveniently performed at room temperature to give a series of homoallylic amines in high yields (up to quant) and diastereoselectivity (up to >99% de). The pure products were obtained by relying on group-assisted purification (GAP) chemistry to avoid traditional purification methods of column chromatography or recrystallization. The conversion of disulfide to (<i>R</i>_<i>s</i>)-thiosulfinate which contains a newly generated polar group was also confirmed to be of the GAP chemistry in which washing crude product can generate pure enantiomer. The absolute stereochemistry has been determined by X-ray analysis

Asymmetric Carbamoyl Anion Additions to Chiral <i>N</i>‑Phosphonyl Imines via the GAP Chemistry Process and Stereoselectivity Enrichments

Carbamoyl anions were found to smoothly react with chiral <i>N</i>-phosphonyl imines in toluene at −78 °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 <i>N</i>-phosphonyl amino amides with good to excellent yields (71–99%) and good crude diastereoselectivities (<i>dr</i> 84:16–95:5). In this GAP procedure, the crude solids are washed with diethyl ether to afford the pure products, as revealed by ¹H NMR analysis; GAP washing consistently increases the diastereopurity of the products, resulting in excellent diastereoselectivities, often with final <i>dr</i> > 99:1. Interestingly, the diastereoenriched products can be obtained either in the ether solution or as the suspended solid, depending on the substrate

Written on the Floor: Shared Theatre Space as Palimpsest

Efficient domino approaches for the synthesis of multifunctionalized tricyclic fused pyrroles and dibenzo[<i>b</i>,<i>e</i>][1,4]diazepin-1-ones have been established. The reaction pathways were controlled by varying enaminones with different substituted patterns to give a series of new fused pyrroles and dibenzo[<i>b</i>,<i>e</i>][1,4]diazepin-1-ones selectively. The complete <i>anti</i> diastereoselectivity was achieved for the first reaction

Parameterization of Acyclic Diaminocarbene Ligands Applied to a Gold(I)-Catalyzed Enantioselective Tandem Rearrangement/Cyclization

Computed descriptors for acyclic diaminocarbene ligands are developed in the context of a gold catalyzed enantioselective tandem [3,3]-sigmatropic rearrangement-[2+2]-cyclization. Surrogate structures enable the rapid identification of parameters that reveal mechanistic characteristics. The observed selectivity trends are validated in a robust multivariate analysis facilitating the development of a highly enantioselective process