Enantiopure η⁴-(1-Sulfinyldiene)Iron(0) Tricarbonyl Complexes as Templates for Carbocycle Construction via Ring-Closing Metathesis

Abstract

[reaction: see text] Enantiomerically pure 1-(1Z,3E)-sulfinyl iron(0) dienols have been elaborated to bis-olefins capable of undergoing ring-closing metathesis chemistry. Using Grubbs' ruthenium carbene catalyst, a six-membered carbocycle (with one chiral center) and seven-, eight-, and nine-membered carbocycles (with two chiral centers) have been prepared. Novel transformations include the LiClO4-promoted allylation of an alkylidene malonate and a reductive sulfur-carbon bond cleavage to convert a vinyl sulfoxide into an alkene with SmI2.

Selective Construction of Carbocyclic Eight‐Membered Rings by Ring‐Closing Metathesis of Acyclic Precursors

“…An interesting example concerns the successful cyclization of an enantiopure h 4 -(sulfinyldiene)irontricarbonyl complex with 8 mol % of 3 in toluene at room temperature to furnish very good yields of the corresponding cyclooctenedienylirontricarbonyl complex (Scheme 34). [71] The presence of the bulky irontricarbonyl unit was suspected to restrict the possible range of conformations for the olefin and thus had a positive effect on the cyclization.…”

Ring-Closing Metathesis Synthesis of Medium and Large Rings: Challenges and Implications for Sustainable Synthesis

“…A similar proportion of dimers was observed by GC-MS (30% and 22% for 10a and 10b, respectively), the mass balance presumably being accounted for by larger, involatile oligomers. Appropriately sited metal substituents can likewise be suitable gearing elements [80,102,103]. Licandro and coworkers reported the construction of seven-, eight-, and nine-membered heterocyclic rings (13a-f, respectively; Figure 12), using a chromium alkylidene substituent a to the acyclic nitrogen group [103].…”

“…Removal of the alkylidene group was not undertaken. Related work has utilized cobalt [80] or iron [102] carbonyl complexes as gearing elements complexed to alkenyl or alkynyl units. These were found to aid in synthesis of structurally more complex seven-to nine-membered rings.…”

“…Paley and coworkers described decomplexation of Fe(CO) 3 from a 1,3-diene moiety in ca. 90% yield, via treatment with FeCl 3 in acetonitrile at -15°C [102]. …”

Large‐Ring Carbocycles

“…117 Enantiopure homoallyl alcohol adduci 232, when treated with 8 mol % of 3 in toluene, gave the corresponding seven-membered ring carbocyle 233 as a single enantiomer in 90% yield. This strategy was also applied to form eight-and nine-membered ring carbocycles with similar success.…”