Derivatives of α,α,α′,α′-Tetraaryl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol (TADDOL) containing nitrogen, sulfur, and phosphorus atoms. New ligands and auxiliaries for enantioselective reactions.
作者:Dieter Seebach、Michiya Hayakawa、Jun-ichi Sakaki、W.Bernd Schweizer
DOI:10.1016/s0040-4020(01)80529-9
日期:1993.2
(5c–5f), as well as a bis(trifluoroacetamide) (5g). Cyclization of the aminoalcohol (4c) produces a bicyclic system (7), containing a pyrrolidine ring (structure determination by X-ray diffraction). - The new chiral compounds containingnitrogen and phosphorusatoms might be useful ligands and auxiliaries for enantioselective syntheses.
been found to occur with 0.5% copper(II) triflate and 1% chiralphosphite. Cyclic phosphites derived from TADDOL gave excellent to moderate enantiomeric excesses. The nature of the exocyclic substituent of the dioxaphospholane ring is important, but the chiral induction is imposed by the TADDOL framework. Syntheses of all the TADDOL ligands are described.
Remarkable Levels of Enantioswitching in Catalytic Asymmetric Hydroboration
作者:Sean M. Smith、James M. Takacs
DOI:10.1021/ol101932q
日期:2010.10.15
phosphites and phosphoramidites are effective ligands for rhodium-catalyzed asymmetric hydroborations of β,γ-unsaturated amides, achieving up to 99% ee. However, the sense of stereoinduction, R or S, is surprisingly dependent on rather subtle features of the ligand. For example, catalysts employing a TADDOL phenylphosphite and those using the closely related N-methylaniline-derived phosphoramidite of the same