Beilstein J. Org. Chem.2016,12, 813–824, doi:10.3762/bjoc.12.80
; dominoaldol; metal enolate; tetrahydropyran; Introduction
Since its discovery in the late nineteenth century the aldol reaction has become one of the most powerful tools in the field of carbon–carbon bond formation [1][2][3][4][5]. It is widely used in the formation of many natural products [6][7][8][9
the years [31]. We have already reported a dominoaldol–aldol–hemiacetal process that furnishes racemic tetrahydro-2H-pyran-2,4-diols in a highly stereoselective manner (Scheme 1) [30][31][32][33][34][35][36][37].
In this paper, the dominoaldol–aldol–hemiacetal reaction involving several metals (Al
, Ga, In, Ti, Zr, Sn), and various aldehydes and ketones is studied experimentally and computationally.
Results
Metal effect
The experiments were performed to screen suitable metal fragments for their ability to promote the dominoaldol reaction by studying the reaction between propiophenone (1a) and
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Graphical Abstract
Scheme 1:
Synthesis of racemic tetrahydro-2H-pyran-2,4-diols rac-5 from enolates 2 and aldehydes 3.