Direct asymmetric catalytic thienylaluminum addition to ketones: a concise approach to the synthesis of (S)-tiemonium iodide.
A direct asymmetric addition of a (2-thienyl)aluminum reagent to ketones catalyzed by a titanium catalyst of (S)-BINOL to afford chiral tertiary 2-thienyl alcohols is reported. The catalytic system works excellently for aromatic ketones and for 1-acetylcyclohexene, furnishing products in excellent enantioselectivities of up to 97% ee. However, the additions to dialkyl ketones afford products in low enantioselectivities of 8-17% ee. Importantly, a concise 3-step synthesis of (S)-tiemonium iodide with an 84% yield is demonstrated.
Biradar
Deepak B
DB
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
Zhou
Shuangliu
S
Gau
Han-Mou
HM
D000438:Alcohols / Q000737:chemistry; D000535:Aluminum / Q000737:chemistry*; D002384:Catalysis; D053138:Cyclohexenes / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D009025:Morpholines / Q000138:chemical synthesis* / Q000737:chemistry; D009284:Naphthols / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry
D000438:Alcohols; C406944:BINOL, naphthol; D053138:Cyclohexenes; D007659:Ketones; D009025:Morpholines; D009284:Naphthols; C520380:acetylcyclohexene; D000535:Aluminum; D014025:Titanium; C003602:tiemonium iodide