Tervalent sulfur atoms

Compounds with o-tervalent sulfur atoms are considered as a special group in Section II, E the parent skeleton is derived by substituting the sulfur atoms with tertiary carbon atoms. 

These compounds, at present hypothetical, contain a cr-tervalent sulfur atom. Theoretical studies were performed16 for models of compounds 122-126 the first two are, in a sense, analogues of bicyclic compounds. In view of their formal similarity with the cyclazines,133 and their positive charge, the tricyclic compounds 124-126 shall be called cyclothiolia. ... 

Rule 2. Tervalent Sulfur Atoms—i.e.. Sulfur Atoms Bonded to Three Other Atoms—Cannot Engage in pir-pir Bonding. This rule is reasonable in view of Rule 1. The lone pair of a tervalent sulfur atom is essentially in a 3s orbital, and extensive hybridization is required to use it in 7T bonding. 

The tervalent sulfur atoms prohibit pw bonding, and the ring has a non-planar conformation, analogous to the chair conformation of cyclohexane (8). However, the ring is nearly planar (the average distance of the nitrogen atoms from the plane of the sulfur atoms is only 0.2 A), and the... 

The structure of SaNsNPPha is shown in Figure 6 (23). Because the tervalent sulfur atom cannot engage in n bonding, the ir bonding is re-... 

New quinolizidines containing phosphine chalcogenide side arms were prepared from the vinyl ether of enantiomerically pure lupinine by the radical addition of R2PH followed by blocking the tervalent phosphorus atom with oxygen, sulfur or selenium (Scheme 13). ... 

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