No abstract

A new diisocyanate, 1,4‐eyclohexane diisocyanate (CHDI), has been used in a series of polyether‐based polyurethane elastomers. The slightly opaque samples are semicrystalline in nature with high performance properties, including high softening temperature, very good thermal stability, high tensile and tear strengths, excellent solvent resistance, and low hysteresis in compressive fatigue. Polymer properties are in part due to the small, compact, symmetrical structure of the aliphatic CHDI. Comparison of the physical, mechanical, and thermal properties of polyurethanes prepared from the aliphatic diisocyanate 4,4′‐dicyclohexylmethane dilsocyanate (H12MDI) reveal the H12MDI polymers to be more flexible and transparent elastomers with lower softening temperatures and tensile moduli and higher hysteretic heat build up. They are generally soluble in organic solvents.

Allylic amines 1 are an important class of compounds in organic synthesis as evidenced by the continuing development of numerous methods for their preparation. 2-12 A characteristic feature of these methods is the narrow range of applicability for generating a wide array of substitution patterns in both cyclic and acyclic amines. It appears that a simple, regioselective synthetic route to allylic amines of diverse substitution patterns is unavailable. We now report that R-aminoalkyl cuprates prepared from CuCN and 2 equiv of tert-butoxycarbonyl-protected R-amino organolithium reagents undergo substitution reactions with enol triflates to afford a direct and efficient synthesis of allylic amines.Organocopper reagents are a powerful tool in the arsenal of synthetic organic chemists, and innovative developments continue to emerge. 13 The reaction of enol triflates with organocuprates 14a,b has recently been extended to allylcuprate 14c reagents. Recently, we reported 15 the development of R-aminoalkyl cuprates as useful reagents for conjugate addition reactions and now report that these reagents undergo substitution reactions with enol triflates to afford allylic amines in good to excellent yields (eq 1). The enol triflates used in this study were readily prepared by established procedures. 16

°C (7 torr), which crystallized in the receiver. Recrystallization from 95% ethanol gave crystals, mp 98-99 °C.Preparation of Dipropionylmesitylene. In a 250-mL three-necked flask fitted with a condenser protected by a drying tube and a magnetic stirrer was placed 5.0 g (0.04 mol) of mesitylene, 14.8 g (0.16 mol) of propionyl chloride, and 75 mL of carbon disulfide. Aluminum chloride (30 g, 0.22 mol) was added to the stirred mixture and the reaction mixture was heated to reflux for 1 h. Carbon disulfide was removed by distillation and the residue was decomposed with ice water, producing a white solid precipitate. The solid was collected on a filter, dried, and recrystallized from petroleum ether (bp 60-80 °C), giving 8.0 g (83%) of white fluffy crystals: mp 101-102 °C (a mixture with 1,1 -dimesitylpropene melted at 77-80 °C); NMR (CDC13) 1.2 (t, 6 ), 2.05 (s, 3 ), 2.18 (s, 6 H), 2.68 (q, 4 H), 7.25 (s,