The Reaction of Dihalocarbenes with Quadricyclane

Article Article scientifique Article The Reaction of Dihalocarbenes with Quadricyclane eng 1985-09-25 author Jefford Charles 24934 author Roussilhe Jacques 76974 author Papadopoulos Mihail 77092 1557-1568 10.1002/hlca.19850680607 0018-019X https://onlinelibrary.wiley.com/doi/10.1002/hlca.19850680607 The reactions of difluoro-, dichloro- and dibromocarbene with quadricyclane (2) were examined. In all cases, conversions were low (4–15%), but three distinct reaction courses were observed: cleavage, 1,2-addition, and 1,4-addition. Difluorocarbene gave mainly 6-endo-(2,2-difluorovinyl)-cis-bicyclo[3.1.0]hex-2-ene (8; 52–89% relative yield), together with minor amounts of exo-3,3-difluorotricyclo[3.2.1.02,4]oct-6-ene (7; 13–17%), and 4,4-difluorotetracyclo[3.3.0.02,8.03,6]octane (5; 2–4%). Dichlorocarbene gave analogous products, but in relative yields of 35 (17), 51 (11), and 12% (16). The product 11 of 1,2-endo addition underwent further rearrangement to its allylic derivative 12. A small amount of 1,2-endo addition also occurred (2% of 14/15). Dibromocarbene gave predominantly products derived from rearrangement of the 1,2-exo (61% of 20/21) and 1,2-endo adducts (10% of 23/24). In addition, a significant amount of 4,4-dibromotetracyclo[3.3.0.02,8.03,6]octane (25; 21%) was formed. The cleavage product, 6-endo-(2,2-dibromovinyl)-cis-bicyclo[3.1.0]hex-2-ene (26) was also observed (7%). The yields and product compositions were compared to those obtained from norbornadiene (1) and found to be entirely different (Table 1), for example no cleavage occurred with difluorocarbene. Dewey 540 36 Département de chimie organique 141 false Helvetica chimica acta 68 6 30488335-02f3-4079-bb1d-fd2a8f93e8a4 Article (Published version) Restricted Helvetica Chimica Acta - 25 Septemb.pdf 806927 application/pdf restrictedAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie organique

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The Reaction of Dihalocarbenes with Quadricyclane	Helvetica chimica acta			1985	201	0

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Roussilhe, Jacques