6.2 [1,2]-Sigmatropic Rearrangement of Onium Ylides -- 6.2.1 Homologation Reactions of Group VI Ylides via Carbene Transfer Reaction -- 6.2.2 Iodonium Ylides -- 6.3 Carbene Insertion Reaction into X X Bonds -- 6.3.1 Insertion Reactions into E E Bonds of Group VI Elements -- 6.4 Ring Expansion Reactions of Oxygen and Sulfur Heterocycles via Homologation Reaction -- 6.5 Conclusions and Perspective -- References -- Chapter 7 Oxenoids as Homologation Partners -- 7.1 General Introduction -- 7.2 Introduction of Oxenoids -- 7.2.1 General Consideration, Structure, and Electrophilic Nature of Oxenoids -- 7.3 Reactions of Oxenoids with Nucleophiles: Homologation Reactions -- 7.4 Conclusions and Outlook -- Acknowledgments -- References -- Chapter 8 Sulfur Ylides as C1 Homologating Reagents -- 8.1 Introduction -- 8.2 Historical Background -- 8.3 Reactivity of Sulfur Ylides as C1 Homologating Reagents -- 8.3.1 Sulfur Ylides in Epoxidation Reactions and Applications in Synthesis -- 8.3.2 Sulfur Ylides as Reagents for the Synthesis of Alkenes -- 8.3.3 Sulfur Ylides as Reagents for the Synthesis of Aldehydes -- 8.3.4 Sulfur Ylides in Aziridination Reactions -- 8.3.5 Sulfur Ylides as Reagents in Miscellaneous Reactions -- 8.4 Reactivity of Sulfoxonium Ylides as C1 Homologating Reagents -- 8.4.1 Sulfoxonium Ylides in Epoxidation Reactions and Applications in Synthesis -- 8.4.2 Sulfoxonium Ylides in Aziridination Reactions -- 8.4.3 Sulfoxonium Ylides in Cyclopropanation Reactions -- 8.4.4 Sulfoxonium Ylides as Reagents for the Synthesis of Indoles -- 8.4.5 Sulfoxonium Ylides as Reagents for the Synthesis of Carbonates -- 8.4.6 Sulfoxonium Ylides as Reagents for Iterative C1 Homologations Leading to Boranes -- 8.4.7 Sulfoxonium Ylides as Reagents in Miscellaneous Reactions -- 8.5 Conclusions -- References.