Recent Advances of α‐Isothiocyanato Compounds in the Catalytic Asymmetric Reaction

Abstract

α‐Isothiocyanato amides, esters and phosphonates have emerged as new types of versatile reagents for various organo‐ and metal‐catalyzed asymmetric cascade reactions, which have attracted increasing interest of many chemists. In this review, recent advances of α‐isothiocyanato compounds for the asymmetric cascade aldol/cyclization, Mannich/cyclization, Michael/cyclization, diverse [3+2] cyclization, and self‐cyclization/addition reactions are summarized and classified according to the types of acceptors.

Organocatalyzed Asymmetric Reaction Using α-Isothiocyanato Compounds

“…In 2013, our group firstly developed an asymmetric cascade aldol/cyclization reaction between α-isothiocyanato phosphonates (6) and aldehydes (11) for the construction of β-hydroxyl-αamino phosphonic acid derivatives (27) [19]. Using bifunctional thiourea catalyst 8d derived from quinine, a range of protected β-hydroxyl-α-amino phosphonates derivatives (27) containing contiguous quaternary-tertiary stereocenters was obtained in up to 93% yield, >99:1 dr, and 81% ee.…”

“…However, isothiocyanato compounds, such as 3-(2-isothiocyanatoacetyl)-oxazolidin-2-one (Figure 1, 1a), were not applied in catalyzed asymmetric cascade reaction until 2005 by Willis. In this process, chiral bis(oxazoline)-magnesium(II) complex was used as catalyst, delivering protected aryl βhydroxyl-α-amino acids in good results [5]. Afterwards, different kinds of isothiocyanato compounds, including α-isothiocyanato amides, esters, and phosphonates (Figure 1), were developed by chemists and applied to the catalytic asymmetric syntheses [6]. In addition, the general methods for the synthesis of α-isothiocyanato compounds were shown in Scheme 1 [5,[7][8][9].…”

Molecular Hybridization-Guided One-Pot Multicomponent Synthesis of Turmerone Motif-Fused 3,3′-Pyrrolidinyl-dispirooxindoles via a 1,3-Dipolar Cycloaddition Reaction

“…Stereoselective construction of spirooxindoles is one of the most challenging tasks in catalytic organic reactions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Generally, isatin and its derivatives have been employed as starting materials in 1,3-dipolar cycloaddition reactions yielding the spirooxindole core [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ] due to the facile preparation of the corresponding azomethine ylides in the presence of α-amino acids [ 50 , 51 , 52 , 53 , 54 , 55 , 56 ], and a variety of 1,3-dipolarophiles such as α,β-unsaturated ketones [ 57 , 58 , …”

Integrative Theory/Experiment‐Driven Exploration of a Multicomponent Reaction towards Imidazoline‐2‐(thi)ones

“…Several (asymmetric) synthetic methods employing α‐acidic isothiocyanates for the synthesis of imidazoline‐2‐thiones have been reported; however, none employ the in situ formation of imines, thus leaving the advantages associated with MCRs unutilized. Furthermore, the known reports describe the employment of either harsh activation or activated imines, which narrow the potential scope of this reaction.…”