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Modular Synthesis of Ar‐BINMOL‐Phos for Catalytic Asymmetric Alkynylation of Aromatic Aldehydes with Unexpected Reversal of Enantioselectivity
Author(s) -
Song Tao,
Zheng LongSheng,
Ye Fei,
Deng WenHui,
Wei YunLong,
Jiang KeZhi,
Xu LiWen
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201301128
Subject(s) - chemistry , stereocenter , catalysis , dimethylzinc , enantioselective synthesis , hydride , phos , alkynylation , lithium (medication) , medicinal chemistry , stereochemistry , combinatorial chemistry , organic chemistry , metal , biochemistry , medicine , endocrinology
An interesting group of multifunctional phosphines (Ar‐BINMOL‐Phos; Ar‐BINMOL=1,1′‐binaphthalene‐2‐α‐arylmethanol‐2′‐ol) with multi‐stereogenic centers of axial and sp 3 ‐central chirality has been prepared successfully from a single chiral source through a concise synthetic route, in which the neighbouring lithium‐promoted [1,2]‐Wittig rearrangement proceeding with excellent diastereoselectivity and enantioselectivity is the key process in this approach. Also, in the catalytic alkynylation of aromatic aldehydes with terminal alkynes, the combination of these Ar‐BINMOL‐Phos ligands with dimethylzinc was found to be an effective catalyst system to afford predominantly the S ‐configured propargylic alcohols, whereas the additional use of calcium hydride and n ‐butyllithium along with the same Ar‐BINMOL‐Phos ligands gave the R ‐configured products in high yields and excellent enantioselectivities (up to >99% ee ).