This review summarises the many advances in the selective transesterification of β-keto esters, with a particular focus on the past 30 years.

A methodology for the asymmetric peroxidation of γ,δ-unsaturated β-keto esters is presented. Using a cinchona-derived organocatalyst, the target δ-peroxy-β-keto esters were obtained in high enantiomeric ratios of up to 95:5. Additionally, these δ-peroxy esters can be readily reduced to chiral δ-hydroxy-β-keto esters without impacting the β-keto ester functionality. Importantly, this chemistry opens up a concise route to chiral 1,2-dioxolanes, a common motif in many bioactive natural products, via a novel P2O5-mediated cyclisation of the corresponding δ-peroxy-β-hydroxy esters.

Study question What are the subsequent pregnancy outcomes (livebirths, miscarriages or other adverse pregnancy outcomes) in a cohort of women with recurrent miscarriage (RM)? Summary answer The overall live birth rate in women with RM was 62% (466/748), falling to 44% in women aged >40 and 54% in women with infertility. What is known already RM affects approximately 1% of women of reproductive age. RM is recognized as a prognostic indicator for subsequent pregnancies and adverse pregnancy outcomes including ante-partum hemorrhage, diabetes, preterm birth, small for gestational age and perinatal death. While RM has known associations with advanced maternal age, obesity, diabetes, thyroid dysfunction and endometriosis, approximately 50% of women/couples will be left without an explanation for their pregnancy loss, even after completing investigations. Study design, size, duration A retrospective cohort study was undertaken to identify subsequent pregnancy outcomes in women with RM, where RM referral criteria are 3 consecutive first-trimester miscarriages. Women attending the pregnancy loss clinic at a tertiary university hospital in the Republic of Ireland over a 12-year period (2008 - 2020) with a confirmed diagnosis of primary or secondary first-trimester RM were eligible for inclusion. In total, 923 charts were identified for review against the eligibility criteria. Participants/materials, setting, methods Women with non-consecutive first trimester miscarriages or ectopic pregnancy were excluded. Epidemiological and clinical information was gathered from paper and electronic medical records. Data were analysed descriptively using SPSS (Version 27). Main results and the role of chance Of 748 women identified, 332(44%) had primary RM, 416(56%) had secondary RM. The median age was 36(range 19-47) years with 12% aged under 29 and 64% of women aged ≥35. 142(19%) had a history of infertility with 43(5.7%) attending for ART. 12% of women had anti-nuclear antibodies(89/742), 8% had abnormal thyroid function tests(60/742), 4.7% were heterozygous carriers of the Factor V Leiden gene mutation(35/737), 1.5% had positive anti-cardiolipin antibodies(11/733), 2% were carriers of a Prothrombin gene mutation(7/343) and 1% had elevated HbA1c levels(7/742). Fetal karyotype was recorded in 141 pregnancies, with 111 abnormal results(78%;111/141). Trisomy(T) 16 was most common(17/111; 15%) followed by T21 and T22(n = 14; 13%). Parental karyotyping of 697 sets of parents identified 28 balanced translocations(4%; 28/697). Prescribed pharmacological treatments included high dose folic acid(75%; n = 548/728), aspirin(96%; 696/726), progesterone (52%; 389/728), tinzaparin(24%; 175/727), prednisolone(4%; 28/726), metformin(2%; 12/727) and hydroxychloroquine(1%; 7/727). 573 women had a subsequent pregnancy (76.6%); 359(62%; 359/573) had a live birth, 190 had a miscarriage(33%) and 18(3%) had an adverse pregnancy outcome such as ectopic pregnancy, stillbirth or second-trimester miscarriage. Including successive pregnancies over the study period, the overall live birth rate was 62%(466/748), falling to 44% in women aged >40 and 54% in women with infertility. Limitations, reasons for caution This work covers a 12-year period, and while the RM clinic staffing is largely unchanged, some changes in management of RM patients has occurred in this time, reflecting up-to-date evidence and greater public awareness. Furthermore, the adoption of an electronic health chart in 2017 may have affected data availability. Wider implications of the findings Our findings confirm RM occurs more frequently in women aged >35. Aneuploidy remains a leading cause of miscarriage. Age is a prognostic indicator for livebirth after RM. These findings will facilitate counselling in this cohort. The substantial rates of prescribed medications and infertility in women with RM merit further exploration. Trial registration number N/A