A convenient synthesis of the traditional medicine constituents magnolamide, lobechine and funebral is described. Construction of the 2‐formylpyrrole core of these natural products was achieved by means of a Maillard reaction, involving condensation of the sugar surrogate, dihydropyranone 9, with the requisite primary amines. This approach offers a very direct and general route to the 2‐formylpyrrole ring system.

The elaboration of a 6,6-spiroacetal scaffold to incorporate a triazole unit as a peptide bond surrogate at the anomeric position is described. The novel spiroacetal-triazole hybrid structures were generated via cycloaddition of a spiroacetal azide to a series of alkynes. The spiroacetal framework was constructed via Barbier reaction of bromide 10 with Weinreb amide 11, followed by acid-catalysed deprotection and cyclisation to afford the 6,6-spiroacetal ring system. The resultant ethoxy-spiroacetal 8 was converted to spiroacetal azide 5, which was then elaborated into a series of spiroacetal-triazole derivatives 7.

The elaboration of a 6,6-spiroacetal scaffold to incorporate a nucleoside unit at the anomeric position is described. The novel spiroacetal-nucleoside hybrids were generated via nucleosidation of acetoxy-spiroacetal with a series of silylated nucleobases under Vorbrüggen conditions.

The first synthesis of a nucleoside analogue 1 is reported wherein the nucleobase 5-fluorocytosine is attached to a 1,6-dioxaspiro[5.5]undecane spiroacetal ring system. The spiroacetal system acts as a substitute for the sugar unit of natural nucleosides and provides a conformationally restricted framework upon which to append nucleobases in a well defined geometry. Trimethylsilyl triflate promoted Vorbrüggen-type coupling of bis(trimethylsilyl)-5-fluorocytosine 3 with spiroacetal acetate 2 provided spiroacetal nucleoside 1 in which the nucleobase occupied an equatorial position together with the ring opened (Z)-alkene 10. Spiroacetal acetate 2 serves as the spiroacetal donor and was prepared from the readily available starting materials δ-valerolactone and but-3-yn-1-ol 4.

The crystal structure of the title compound, C30H38N2O5Si, has been investigated to establish the relative stereochemistry at the spiro ring junction and the two anomeric centres. Each of the O atoms in the tetra­hydro­pyran rings adopts an axial position on the neighbouring ring. This bis­-diaxial conformation is adopted, thus gaining maximum stablization from the anomeric effect. The silyl-protected hydroxy­methyl and uracil substituents adopt equatorial positions on their associated tetra­hydro­pyran rings, thereby minimizing unfavourable steric inter­actions. The dimeric (2′R*,6′R*,8′R*)- and (2′S*,6′S*,8′S*)-uridine units are connected to each other across crystallographic inversion centres via inter­molecular N—H⋯O hydrogen bonds.