Over the past 15 years the Corey-Chaykovsky (CC) epoxidation process 1 involving the reaction between sulfonium ylides and aldehydes has evolved into a highly synthetically useful, catalytic asymmetric methodology. 2The use of semistabilized ylides such as those derived from the reaction of either benzyl halides or α-haloesters/amides with chiral sulfides at catalytic loadings can result in excellent levels of product enantiomeric excess.3 In stark contrast however, the asymmetric synthesis of terminal epoxides via methylene transfer is characterized by moderate yields and a requirement for (super)stoichiometric loadings of chiral sulfide catalysts. 4,5 For example, the benchmark literature procedures (Scheme 1) for the asymmetric sulfonium ylide-mediated formation of styrene oxide (2) from the archetypal substrate benzaldehyde (1) developed independently by Aggarwal 6a,b and Goodman 6c involve the use of 100-200 mol% of the chiral sulfides 3-4 and produce 2 in ca. 50-60% yield and <60% ee. 7 Hiyama et al. (ref. 7a) claimed that 2 could be synthesized in 97% ee in the presence of a chiral phase transfer catalyst. However our group (ref. 7b) recently demonstrated that Hiyama was in error and has actually observed the decomposition of the catalyst to a related epoxide (with a relatively large specific rotation) during the formation of 2 as a racemate: (a) Hiyama, T.; Mishima, T.; Sawada, H.; Nozaki, H. J. Am.