C-Metallierte Chirale Alkoxide als d2- and d3- Reagenzien fuer die Synthese enantiomerenreiner Producte (EPC-Synthese)

Article abstract of DOI:10.1002/hlca.19840670135

The chloroalcohols (S)-1-chloro-2-propanol (1), (S)-1-chloro-2-methyl-2-pentanol (4), (R)-3-chloro-2-methyl-1-propanol (7), (R)-4-chloro-2-butanol-(10), and (2R,3R)-4-chloro-3-methyl-2-butanol (14), readily available from the esters of lactic, 3-hydroxy-2-methylpropionic, and 3-hydroxybutanoic acid are subjected to sequential metallation first with BuLi (or MeMgCl) and then with lithium naphthalenide (or Li metal powder) to give solutions of the highly reactive C-metallated alkoxides 15,22, 26, 27, and 28 respectively.- These chiral d²- and d³-reagents may be added to aldehydes ( non-diastereoselectively), ketones and CO2 to give 1,3- or 1,4-dioles (18-21, 14, 29-33) or γ-lactones (35,36).Thiolations with dibenzyl disulfide (->16, 34) and a deuteration ( ->17, (S)-(1-2H)propan-2-ol) were also carried out.Independent synthesis of (S)-1-benzylthio-2-propanol (16) and comparison of the specific rotations establish that no loss of enantiomeric purity occurs on the metallation route.The results described represent an extension of the applicability of simple chiral building blocks to EPC-synthesis.