ChemInform Abstract: C₁‐Symmetric Rh/Phebox‐Catalyzed Asymmetric Alkynylation of α‐Ketoesters.

Abstract

C 1 -Symmetric Rh/Phebox-Catalyzed Asymmetric Alkynylation of α-Ketoesters. -The title complexes (I) and (II) catalyze the process with good yields (up to 95%) and enantioselectivities (up to 99% e.e.) under mild conditions. Introduction of a p-nitro group [→ (IIb)] enhances the reactivity for less reactive substrates. The propargylic aldehyde (Vd) is prepared without protection/deprotection of the carbonyl group. -(OHSHIMA*, T.; KAWABATA, T.; TAKEUCHI, Y.; KAKINUMA, T.; IWASAKI, T.; YONEZAWA, T.; MURAKAMI, H.; NISHIYAMA, H.; MASHIMA, K.; Angew. Chem., Int. Ed. 50 (2011) 28, 6296-6300, http://dx.doi.org/10.1002/anie.201100252 ; Grad. Sch. Pharm. Sci., Kyushu Univ., Higashi, Fukuoka 812, Japan; Eng.) -Kieslich 48-070