Efficient Tandem Morita-Baylis-Hillman/Double Cross-Aldol Reaction between Cyclic Enones and Formaldehyde Promoted by N-Methylpyrrolidine

• Published in: European Journal of Organic Chemistry 2011-04, Vol.2011 (12), p.2372-2379
• Main Authors: Guerra, Krassimira P., Afonso, Carlos A. M.
• Format: Article
• Language: English
• Subjects: Aldehydes; Aldol reactions; Alicyclic compounds; Alicyclic compounds, terpenoids, prostaglandins, steroids; Allylic compounds; Chemistry; Domino reactions; Enones; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Kinetics and mechanisms; Organic chemistry; Preparations and properties; Reactivity and mechanisms
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201001612

The Lewis base N‐methylpyrrolidine acts in water as an efficient promoter of tandem reactions between 2 cyclopenten‐1‐one and aqueous formaldehyde. The reaction pathway includes, as consecutive independent steps, a MBH reaction and a double cross‐aldol reaction to furnish the new 2,5,5‐tris(hydroxymethyl)‐2‐cyclopenten‐1‐one in excellent yield. A range of cyclic enones and 4‐nitrobenzaldehyde undergo the tandem reaction similarly. The reaction mechanism was also investigated. A simple environmentally friendly domino Morita–Baylis–Hillman (MBH) cross‐aldol addition reaction in water with 2‐cyclopent‐1‐one or other cyclic enones and formaldehyde as partners is disclosed. The novel 2,5,5‐tris‐(hydroxymethyl)‐2‐cyclopentenone was isolated in 91 % yield, and similar reactivity was observed for other cyclic enones.