Sequential Insertion of Formaldehyde and Carbon Monoxide into a Sulfide-Bridged Pd−Ge Bond Followed by Reductive Elimination To Form a [1,3,2]Oxathiagermolan-4-one

The reaction of <ETIEBAR ID="om049944da10001">(Et<INF>3</INF>P)<INF>2</INF><TIEBAR NUM="om049944d00000">Pd(μ-S)</TIEBAR>Ge[N(SiMe<INF>3</INF>)<INF>2</INF>]<INF>2</INF></ETIEBAR> (<BO>2</BO>) with paraformaldehyde under photolytic conditions results in the insertion of formaldehyde into the Pd−Ge bond, with bond cleavage, to give (Et<INF>3</INF>P)<INF>2</INF>Pd(μ-S)(μCH<INF>2</INF>O)Ge[N(SiMe<INF>3</INF>)<INF>2</INF>]<INF>2</INF> (<BO>3</BO>). Subsequent addition of CO to <BO>3 </BO>results in migratory insertion into the Pd−C bond, followed by rapid reductive elimination to regenerate the Pd⁰ metal center and give a unique five-membered organic heterocycle, <ETIEBAR ID="om049944da10002"><TIEBAR NUM="om049944d00000">Ge[N(SiMe<INF>3</INF>)<INF>2</INF>]<INF>2</INF>SC(O)CH<INF>2</INF></TIEBAR>O</ETIEBAR> (<BO>6</BO>). The X-ray crystal structure of the dppe (dppe = bis(diphenylphosphino)ethane) derivative of <BO>3</BO>, (dppe)Pd(μ-S)(μCH<INF>2</INF>O)Ge[N(SiMe<INF>3</INF>)<INF>2</INF>]<INF>2</INF> (<BO>4</BO>), is reported.