N-acylthiazolidinethiones

The chlorotitanium enolates derived from AT-acyloxazolidinones 3.17, N-acyloxazolidinethiones 3.18 and iV-acylthiazolidinethiones 3.19 undergo highly selective and efficient aldol reactions with aldehydes. The iST-acyloxazolidinethione 3.18 and N-acylthiazolidinethione 3.19 auxiliaries are also easier to cleave. 

The Ni(II) Tol-BINAP-catalyzed enantioselective orthoester alkylation of N-acylthiazolidinethiones 158 is carried out using 5 mol% of (5)-Ni(ll) Tol-BINAP 157 to provide 159 in good yields and with excellent enantioselectivities <05JA10506>. 

Similarly, MgBr2-Et20 was proved to be an effective catalyst in the di-astereoselective direct anti-aldol reaction of chiral AT-acylthiazolidinethiones in the presence of triethylamine and chlorotrimethylsilane. Grood yields (56-93%) and diastereoselectivities (up to 19 1) were obtained for a variety of N-acylthiazolidinethiones and unsaturated aldehydes (140). 

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