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  • Enantioselective direct aza hetero-Diels-Alder reaction catalyzed by chiral Brønsted acids.

Enantioselective direct aza hetero-Diels-Alder reaction catalyzed by chiral Brønsted acids.

Organic letters (2006-12-15)
Hua Liu, Lin-Feng Cun, Ai-Qiao Mi, Yao-Zhong Jiang, Liu-Zhu Gong
ABSTRACT

[Structure: see text] The first chiral Brønsted acid-catalyzed asymmetric direct aza hetero-Diels-Alder reaction has been described. The phosphoric acids, prepared from binol and H8-binol derivatives, have shown catalytic ability for the reaction of cyclohexenone with N-PMP-benzaldimine. A chiral phosphoric acid, derived from 3,3-di(4-chloropheneyl)-H8-binol, exhibited superior enantioselectivity, affording fairly good yields and enantioselectivities for the reaction of a range of aromatic aldimines with cyclohexenone.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
(R)-(+)-3,3′-Bis(3,5-bis(trifluoromethyl)phenyl)-1,1′-bi-2-naphthol, 95%
Sigma-Aldrich
(R)-3,3′-Bis(triphenylsilyl)-1,1′-bi-2-naphthol, 96%