Palomo, ClaudioOiarbide, MikelGómez Bengoa, EnriqueMielgo, AntoniaGonzález Rego, María ConcepciónGarcía Castillo, Jesús MaríaGonzález Guerrero, AlbertoOdriozola Ibarguren, José ManuelBañuelos, PatriciaLinden, Anthony2017-02-102017-02-1020051424-6376https://academica-e.unavarra.es/handle/2454/23502The presented lithium enolate-based methodology is suitable for access to propionate syn-aldol motifs with high levels of stereocontrol. The reactive lithium enolate species is generated by direct treatment of a camphor-based chiral ethyl ketone with butyllithium, and is subsequently submitted to aldolization with a broad variety of aldehydes. The product aldols are obtained in uniformly high yields and high d.r. values (ranging from 91:9 to >98:2) irrespective of the aliphatic (both linear and branched chain), α,β-unsaturated, aromatic, or hetero-aromatic nature of the aldehyde employed. The crystallinity of most of the obtained adducts offers an easy access to almost 100% isomerically pure products upon a single recrystallisation. The auxiliary (1R)- (+)-camphor can be removed easily from the adducts for reuse, thereby producing the corresponding syn propionate aldols. This technology is implemented in the synthesis of a key subunit of the multi-drug resistance reversing agent hapalosin.16 p.application/pdfeng©ARKAT USA, Inc.Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)Lithium enolatesAldol reactionAsymmetric synthesisHapalosinButyllithiumArtículo / ArtikuluaAcceso abierto / Sarbide irekiainfo:eu-repo/semantics/openAccess