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Selektive Herstellung von l ‐ oder u ‐Aldolen aus Äthyl‐trityl‐keton und aromatischen Aldehyden über Lithium‐ bzw. Aluminium‐Enolate by Mümtaz Ertaş; Dieter Seebach is a Chemistry article available to read on EtoBox.

What is Selektive Herstellung von l ‐ oder u ‐Aldolen aus Äthyl‐trityl‐keton und aromatischen Aldehyden über Lithium‐ bzw. Aluminium‐Enolate about?

**Selective Preparation of __l__‐ or __u__‐Aldols from Ethyl Trityl Ketone and Aromatic Aldehydes through Lithium and Aluminium Enolates, Respectively** The ethyl trityl ketone (**1**) is deprotonated to the (__Z__)‐enolate **2** which adds to aromatic aldehydes with relative topicity __ul__ to give the aldols **3**(−78°, THF, kinetic control). If, on the other hand, **1** is heated with trimethylaluminium in toluene, the aluminium enolate formed combines with aromatic aldehydes and with cinnamic aldehyde with opposite relative topicity __(lk)__ to the aldols **5** (+20°, toluene, 2 d, precipitation of the aluminium aldolate **4**, thermodynamic control). The mechanism is discussed __(cf. Fig. 1)__. The adducts to benzaldehyde (**3a**, **5a**), furfural (**3f**, **5f**), and cinnamaldehyde (**3i**, **5i**) are __O__‐(2‐methoxyethoxy)methyl (MEM) protected and cleaved by lithium triethylborohydride to the 1,3‐diol derivatives **9–11** with a free primary and a protected secondary OH‐group. Analogous conversions of **1** and other ketones may also be diastereoselective, but turned out to be of less preparative value (see **6–8**, **12**).

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Author

Mümtaz Ertaş; Dieter Seebach

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); Wiley-Blackwell; Wiley (ISSN 0018-019X)

Published

1985

Language

DE

Field

Chemistry (Physical Sciences)