Stereoselective Electrophilic Cyclizations of δ-Aminoalkenes Derived from Carbohydrates; Synthesis of Polyhydroxypiperidines

Abstract

Electrophilic cyclizations of a carbohydrate-derived δ-aminoalkene were studied. Iodocyclizations proceeded with moderate steric control to afford the D-gluco-configured piperidine as the major product. More extensive studies with mercuric salts resulted in the definition of new reaction conditions for aminomercuration that give higher, reversed stereoselection. The aminomercurations were also amenable to the use of a range of mercuric salts. These aminomercurations may be under chelation control with substrate allylic benzyloxy substituents. The configurations of the piperidine products were confirmed by elaboration of one bromomercurial to a known aminoalditol by oxydemercuration and hydrogenolysis.

Hydroamination: Direct Addition of Amines to Alkenes and Alkynes

“…524,525 In the field of aza-sugars, carbohydrate-derived δ-aminoalkenes have been cyclized under different conditions (iodine-or mercury(II)-promoted amination) to study the stereoselection of the process. 526 This chemistry was employed for the preparation of N-acetylglucosaminidase inhibitors from a methyl manopyranoside, the key step being shown in Scheme 122 for the transformation of compound 273 into a mixture of diastereomers 274 and 275, which then were oxidized as it was above mentioned (Scheme 121). 527 The same methodology was used to prepare the enantiomerically pure cyclic aminoalditols 1-deoxynojirimycin and 1-deoxymannojirimycin.…”

Applications of the amino-Cope rearrangement: synthesis of tetrahydropyran, δ-lactone and piperidine targets

“…C 12 H 13 IO 2 , M = 316.12, orthorhombic, P2 2 2 1 2 1 , a = 6.6491(4), b = 6.8227(4), c = 25.8973(14) A ˚, V = 1174.83(12) A ˚3, Z = 4, wR = 0.0338 for all 2793 unique data, R1 = 0.0150 for 2708 data with F 2 ≥ 2r(F 2 ). Absolute structure parameter = 0.001 (16), thus reliably determined. CCDC reference number 206872.…”

Stereoselective Synthesis of Piperidines

“…Among the very few catalytic asymmetric syntheses of piperidines the method developed by Deziel should be mentioned (Scheme 16 37 However, both iodonium-mediated cyclization and the corresponding cyclizations via mercurinium ions proceeded only with low diastereoselectivity (d.r. < 63:37).…”