Synthesis of aromatic and αβ-unsaturated aldehydes by a friedel-crafts-like electrophilic destamylation using 1,1-dichloromethyl metyhyl ether

Article abstract of DOI:10.1002/cber.19961290111

A mild and effective method for the preparation of a variety of aromatic (7a-m), heteroaromatic (7n-r), and α,β-unsaturated aldehydes (8a-f) is described. The reaction of trialkylaryl- (2a-o), heteroaryl- (2p-t), and 1-alkenylstannanes (4a-f and 5a-f) with dichloromethyl methyl ether (1, DCME) in the presence of aluminium trichloride followed by hydrolysis provides the corresponding aldehydes. In the case of arylstannanes the ipso-isomers are generally formed; the p-alde-hydes occur as side products. The electrophilic substitution of 1-alkenylstannanes with 1 leads to α,β-unsaturated aldehydes In an ipso- and stereospecific manner. A comparison of the leaving abilities of the stannyl and silyl groups shows a lower or even zero reactivity of the silyl-substituted compounds 8a-e towards the electrophile 1. In the silylstannylalkene 6c only the stannyl group reacts whereas the stannyl function remains unaffected in the product, aldehyde 11.