Branched triangulane

New procedures, in addition to the previous one, were developed to obtain higher branched triangulanes [174]. 

The addition of methylchlorocarbene onto bicyclopropylidene (1) (Scheme 26) and functionalized bicyclopropylidenes like 44a and 121 has been used as a key step in the synthesis of branched triangulanes [53,122-1241. This was applied... 

Scheme 27. Preparation of branched triangulanes 128,129 via carbene cycloadditions [33,65,105]...

Both procedures were successfully used for the preparation of branched triangulanes 50 and 51 as well as for the previously unavailable [6]triangulane 5570,73 75. 

The preparation of other branched triangulanes with varying symmetries has also been reported. A notable feature of this series of small hydrocarbon cascades is that the framework is composed entirely of quaternary, tetraalkyl-substituted carbons. This unique architecture closely resembles or is at least reminiscent of Maciejewski s 16 proposed cascade molecule comprised of an all 1 — 3 C-branched interior framework (i.e., without spacers between branching centers). 

Scheme 4.17. Synthesis of branched triangulane possessing adjacent, quaternary carbon moieties. R = Me or THR...

In addition to linear and branched triangulanes, a new class of triangulanes, cyclic triangulanes 3 (CT), has been proposed as an additional subclass of triangulanes. ... 

A sequence of carbene additions to methylenetriangulanes can be used to build branched triangulanes. i - 3 3 When chloro(methyl)carbene generated from 1,1 -dichloroethane with butyl-lithium is used, new exocyclic double bonds for further cyclopropanation reactions can be generated by HCl elimination. For the same purpose l,l-dichloro-3-methoxypropane... 

---