Smith-Tietze coupling

The already called Smith-Tietze coupling reaction has been used in the synthesis of the bryostatin B ring by using glycidol 192 as the only electrophile317. When C2-symmetric... 

The stereocontrolled enantioselective synthesis of an advanced B-ring synthon of bryostatin 1 was achieved in the laboratory of K.J. Hale. " The key step was a Smith-Tietze coupling of 2-lithio-2-TBS-1,3-dithiane with a homochiral epoxide in the presence of HMPA. The resulting dithiane alkoxide was trapped with TBSCI in situ followed by deprotection of the dithiane moiety to give a Crsymmetrical ketone. This ketone was then further elaborated into the target B-ring synthon. 

Hale, K. J., Hummersone, M. G., Bhatia, G. S. Control of Olefin Geometry in the Bryostatin B-Ring through Exploitation of a Cj-Symmetry Breaking Tactic and a Smith-Tietze Coupling Reaction. Org. Lett. 2000, 2, 2189-2192. 

SMITH-TIETZE MULTICOMPONENT DITHIANE LINCHPIN COUPLING... 

Smith-Tietze Multicomponent Dithiane Linchpin Coupling. 

Smith et al. have developed a very elegant route to complex polyol structures by sequential dithiane-epoxide coupling reactions (Scheme 7) [16]. Following the work of Tietze [17], 2-silyl-1,3-dithianes 42 are deprotonated with /BuLi in ether and converted into the stable lithium alk-oxides 43 with enantiomerically pure epoxides. A fast 1,4-Brook rearrangement occurs only after the addition of 0.3 equivalents of hexamethyl-phosphoramide (HMPA) or 1,3-dimethylhexahy-dro-2-pyrimidone (DMPU) to the reaction mixture. A new lithiated dithiane 44 that can undergo... 

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