Homo-Reformatsky reaction

Table 7. 4-Siloxy esters by ZnX2-catalyzed Homo-Reformatsky reaction (Ref. [29, 33])...

The synthesis started with the homo-Reformatsky reaction between the alkoxytitanium homoenolate Eq. (30) and aldehyde 27, which afforded the product 28 with Cram orientation with >6 1 selectivity. An inversion at the sterically hindered C22 position was readily achieved by mesylation, followed by KOH treatment in hot aqueous MeOH to give lactone 30 after add-catalyzed lactonization. 

Homo-Reformatsky reaction.1 The reaction of 1-ethoxy-1-trimethylsilyloxy-cyclopropane (1) with an aldehyde in the presence of ZnCl2 results in y-silyloxy esters via a zinc homoenolate (a) of ethyl propionate (equation I). Znl2 is the preferred catalyst in the case of reactions with acetophenone and benzaldehyde dimethyl acetal and in reactions of l-isopropoxy-l-(t-butyldimethylsilyl-oxy)cyclopropane with aromatic aldehydes. 

Homo-Reformatsky-Reaction 2025 Wieland-Miescher-Ketone 1990... 

Synthesis of a marine sterol, depresosterol (25), illustrates the utility of the homoenolate as a multifunctional, three-carbon building block. Homo-Reformatsky reaction between an alkoxytitanium homoenolate (11 Section 1.14.5.1) and an aldehyde (19) afforded the undesired Cram product (20) in a ratio of >6 1 (Scheme 29). Inversion of the stereochemistry at the sterically hindered C-22 position was achieved through internal solvolysis by taking advantage of the terminal ester function. Stereoselective hydroxymethylation of the lactone (22) followed by introduction of the C-26 and C-27 methyl groups to (23) afforded depresosterol (25). 

Amino acid esters via a homo-Reformatsky reaction (p. 80)... 

Palladium catalysis promotes the Reformatsky reaction. Heteroaryl iodides are better substrates than bromides and chlorides. Iodine in electrophilic positions in the substrate, but not in the benzenoid position, were active in the Reformatsky reaction (277,278) (Scheme 63). Homo-coupling is the major pathway for iodo derivatives in the benzenoid position, with formation of 3,3 -biquinoline (279) (85CPB4309). 

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