Acyldithiane oxides

Alkylation and acylation of dithiane oxides are highly stereoselective processes. In such transformations, it is noticed that the anti substrate leads to the syn acyldithiane oxide (Scheme 4.55), with the choice of base being pivotal in the process. The use of butyllithium for acylation and sodium t-butoxide/butyllithium mixtures for alkylation with aldehydes tends to give the cleanest and most efficient reactions. Of late, simple 2-substituted dithiane oxides have been prepared with very high enantioselectivity, and such compounds have become the preferred starting materials for the various systems under scrutiny. 

Grignard reagents add efficiently to acyldithiane oxides to furnish tertiary alcohols in excellent yields and without loss of the dithiane oxide unit by nucleophihc displacement (Scheme 4.59) [112]. 

Introduction of nitrogen into acyldithiane oxide systems the Mannich reaction... 

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