3-Iodolevoglucosenone and chiral cyclopropane

Abstract

Using the reaction of the malonate anion with iodovinyl ketone (2) obtained from levoglucosenone (1) t,2 as an example, we suggest a new approach for the construction of the enantiomerically pure functionalized type 3 cyclopropanes that find wide applications in organic synthesis. 3-5

Stereoselective Cyclopropanation Reactions

“…The reactions involving sulfur ylides and substituted cyclohexenones are well known to proceed with very high diastereoselectivities under steric control, although in some cases, stereoelectronic arguments could also be invoked 289a. For example, the cyclopropanation of ( R )-(−)-carvone ( 299 ) with methylenedimethylsulfoxonium provides the desired cyclopropylcarvone 300 in 95% yield, as a single diastereoisomer, which results from the attack of the ylide on the less hindered face (eq 85). ,

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Palladium‐Catalyzed Suzuki–Miyaura, Heck and Hydroarylation Reactions on (–)‐Levoglucosenone and Application to the Synthesis of Chiral γ‐Butyrolactones

“…We have found no reports of Suzuki–Miyaura reactions that use 2 despite this seeming a straightforward way to further functionalize LGO. Iodination of LGO with I 2 /pyridine afforded 3‐iodolevoglucosenone ( 2 ) in 96 % yield 11a,15. The isolation of 2 required only filtration through a pad of silica gel then evaporation of volatiles and so could be performed on a multi‐gram scale.…”

“…(1 S ,5 R )‐3‐Iodo‐6,8‐dioxabicyclo[3.2.1]oct‐2‐en‐4‐one (2): 11a,15 To a solution of 1 (1.5 g, 11.9 mmol) in 1,2‐dichloroethane (20 mL) was added I 2 (4.2 g, 16.5 mmol), then pyridine (1.08 mL, 13.4 mmol), and the reaction mixture was stirred for 15 min. Toluene (20 mL) was added and the resulting suspension poured onto a 5 cm plug of silica and the product eluted with toluene.…”

Tandem transformations initiated and determined by the Michael reaction

“…38 Thus the reactions of readily accessible Cyclopropane derivative 81 was synthesised by the reaction of the malonate anion with 3-iodolevoglucosenone ( 69) as an electrophilic component. 39 Apparently, a 1,3-shift of electron density occurs in the intermediate carbanion A resulting in generation of the more stable carbanion B, which eliminates the iodide ion to give the product 81 containing the cyclopropane ring.…”