Iterative, Programmable, and Controllable De Novo Synthesis of Fully Heteroleptic All-Carbon Substituted Silanes from Four Different Organometallic Reagents

All-carbon substituted silanes are a class of unnatural yet important compounds. To access them from SiCl4 or Si(OR)4 and organometallic reagents is intuitively the most straightforward de novo approach, which unfortunately is only applicable to homoleptic but not heteroleptic ones. Thus, alternative silyl precursors and techniques to enable controllable substitutions at silicon are highly desirable. Herein, we targeted the structurally most complicated and synthetically most challenging fully heteroleptic all-carbon substituted silanes and developed Ph3SiCl and Ph2Si(OMe)2 as the synthetic equivalent of SiCl4 or Si(OR)4 for the de novo synthesis of them. Mono-selective dephenylative etherifications of triphenyl-substituted silanes as well as diphenyl-substituted ones were key to success. Within 5-7 steps, four different carbon units from organometallic reagents could be ligated to one silicon center in a controllable, programmable, and iterative fashion. Meanwhile, unique reactivities of hexafluoroisopropoxysilanes and silanes with hemicrown ether auxiliaries in organometallic substitution reactions were disclosed.