Diastereo‐ and Regioselective Addition of Thioamide Dianions to Imines and Aziridines: Synthesis of N‐Thioacyl‐1,2‐diamines and N‐Thioacyl‐1,3‐diamines

Abstract

Addition reactions of thioamide dianions that were derived from N-arylmethyl thioamides to imines and aziridines were carried out. The reactions of imines gave the addition products of N-thioacyl-1,2-diamines in a highly diastereoselective manner in good-to-excellent yields. The diastereomeric purity of these N-thioacyl-1,2-diamines could be enriched by simple recrystallization. The reduction of N-thioacyl-1,2-diamines with LiAlH(4) gave their corresponding 1,2-diamines in moderate-to-good yields with retention of their stereochemistry. The oxidative-desulfurization/cyclization of an N-thioacyl-1,2-diamine in CuCl(2)/O(2) and I(2)/pyridine systems gave the cyclized product in moderate yield and the trans isomer was obtained as the sole product. On the other hand, a similar cyclization reaction with antiformin (aq. NaClO) as an oxidant gave the cis isomer as the major product. The reactions of N-tosylaziridines gave the addition products of N-thioacyl-1,3-diamines with low diastereoselectivity but high regioselectivity and in good-to-excellent yields. The use of AlMe(3) as an additive improved the efficiency and regioselectivity of the reaction. The stereochemistry of the obtained products was determined by X-ray diffraction.

Diastereoselective Electrophile‐Directed Alkylations

“…Vinyl or alkynyl azaallyl anions (R 1 = CH=CH 2 , CH=CMe 2 , Me 3 SiCC) produce good yields but the diastereoselectivities drop to 3–2.5:1. Comparable aziridine ring openings with the dianion derived from PhCH 2 NH(C=S)Ph are significantly less selective, dr ≤ 4:1 …”

Charge-assisted N(+)–H···(−)S hydrogen bonds in the crystal structure of selected diammonium thiophenolates

“…The Cambridge Structural Database (CSD) version 5.36 (February 2015 update) [11] was now examined to find out the generality of occurrence of crystal structures which contain NÁÁÁHÁÁÁS interactions. Inert systems featuring N-HÁÁÁS can be found in the thiocarbonyl [12][13][14][15] or thioether [16] compounds. Second, electrically neutral NÁÁÁH-S hydrogen bonds are rarely found in the solid state [17][18][19], because the SH group is a weak proton donor and forms bonds of low energy.…”

Kinetic Resolution of Secondary 2‐Aryl‐1‐cycloalkanols with Phosphoroselenoyl Chloride with a Binaphthyl Group

“…We recently developed phosphoroselenoic acid derivatives bearing a 1,1′‐binaphthyloxy group as new chiral molecular tools in our studies on organochalcogen compounds . The starting chlorides 1 are readily prepared by reacting PCl 3 with binaphthol and elemental selenium in the presence of a base (Scheme ).…”